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Pelican Technical Article:

BMW Alternator
Troubleshooting and
Replacement

Difficulty Level: 4
Difficulty scale: Adding air to your tires is level one
Rebuilding a BMW Motor is level ten

  This article is one in a series that have been released in conjunction with Wayne's new book, 101 Performance Projects for Your BMW 3 Series. The book contains 272 pages of full color projects detailing everything from performance mods to timing the camshafts. With more than 650+ full-color glossy photos accompanying extensive step-by-step procedures, this book is required reading in any 3 Series owner's collection. The book was released in August 2006, and is available for ordering now. See The Official Book Website for more details.
 
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[click to enlarge]

     One of the nice things about the configuration of the BMW engine is the relative ease with which you can replace the alternator. The alternator is nestled neatly on the left side of the engine compartment and is easily accessible. The replacement and repair process is straightforward and should take you about an afternoon to complete.

    
First, make sure your alternator is indeed the cause of the problems with your charging system. Sometimes bizarre electrical problems can be caused by a number of faults other than the alternator. It’s important to troubleshoot the system prior to replacing your alternator.

    
The first component to check, then, is the belt that drives the alternator. Is it tight and amply turning the fan? If not, tighten it according to the procedures outlined in Project 5. Modern belts seldom break, but they do get brittle and glazed with age, and can slip on their pulleys. Replace it with a new one if it looks cracked or brittle.

    
The next item to check is the voltage at the battery. This should read a little more than 12 volts with the engine off. When the car is running, the voltage should read at in the range of 13 to 14.5 volts with the engine at 2,000 rpm. If your battery appears to be leaking, your voltage regulator has probably failed. The battery will usually only leak acid if it has been overcharged at a much higher voltage. If the voltage measured at the battery is more than 16 or 17 volts when the engine is running, the regulator is probably bad. If your battery has boiled over and has acid flowing out the top, clean it up immediately. Dousing the area with a water-and-baking-soda solution should help considerably to neutralize the acid and prevent it from eating away at the metal.

    
An important item to check on your car is the engine ground strap. The engine is electrically isolated from the chassis by rubber motor mounts. If the engine ground strap is missing or disconnected, you might have a whole bunch of problems, including electrical system malfunctions and difficultly turning over the starter. (See Project 85 for the exact location of this ground strap.) Also, some BMW alternators have an external ground that may get disconnected accidentally.

    
Almost all the 3 Series cars have a replaceable voltage regulator/brush assembly. If you’ve determined the regulator to be working properly, then you should probably remove the alternator for testing and inspection. Before starting any work, make sure you disconnect the battery. The positive battery terminal is directly connected to the alternator, and it can be dangerous to work on if it’s live (see Project 84).

     The first step in removing the alternator is to remove the belt that drives it. (See Project 5 for detailed instructions on belt removal.) Now removing the alternator from its bracket is a very easy process. On the early 3 Series, the alternator is affixed to the car via a pivot bolt, and a rack-and-pinion assembly is used to adjust the belt tension. Disconnect the rack-and-pinion assembly if your car has one (see Photo 2), and unbolt the alternator from its bottom pivot bolt. For the later E36 cars, the alternator is fixed in place, and the multifunction belt is tightened on the alternator with a spring-loaded tensioner pulley (see Project 5 for details and photos). Simply unbolt the alternator from where it’s attached to the engine after removing the belt. Depending upon which engine you have, you may need to remove some equipment such as the air cleaner and cool air guide located above the alternator. See Project 12 for details on removing components that are in the way.

     With the alternator unbolted, disconnect the electrical connections from the rear. I recommend taking a digital photo of the connections, because many people mix them up when reinstalling the alternator. If you make a mistake and hook them up incorrectly, it’s possible to do some significant damage to your electrical system. Reminder: Do not touch any of these connections while the battery is still hooked up! (Review Project 84 for additional details).

    
With the alternator out of the car, remove and inspect the regulator/brush assembly (see Photo 4). If you are replacing the alternator completely, transfer the old pulley assembly to the newly rebuilt alternator (see Photo 3). Installing the new alternator is now simply the reverse of removal. Make sure you reconnect all the wires to their proper terminals when you are done.

     If you would like to see more technical articles like this one, please continue to support Pelican Parts with all your parts needs.  If you like what you see here, then please visit our online BMW catalog and help support the collection and creating of new and informative technical articles like this one.  Your continued support directly affects the expansion and existence of this site and technical articles like this one.  As always, if you have any questions or comments about this helpful article, please drop us a line.

Figure
Figure 1
Here is an alternator nestled into the engine compartment on an E30 318i. It’s relatively easy to reach, although on some models, you may have to remove the air cleaner and some hoses to completely pull it out.
Figure
Figure 2

Shown here is the rack-and-pinion system used to apply tension to the belt on early cars. Loosen the bolt at the rear of this bracket before you try to turn the front toothed bolt. If you don’t, you will break off teeth on the rack and thus make it very difficult to tighten the alternator belt. This particular bracket has been abused and has suffered the loss of one tightening tooth (red arrow).

Figure
Figure 3
I’ve never seen a new or rebuilt alternator supplied with the pulleys attached, so you’ll need to transfer them from your old unit. Removing the pulley can be tricky if you don’t have an impact wrench (good reason to buy an electric one). Also useful may be a strap wrench, which is a handle with a rubber strap on it that can secure and tighten around a pulley. These four frames show the removal and reinstallation of the pulley on an E30 318i alternator. Be sure to take notes as you disassemble the alternator pulley assembly—it must be reassembled in exactly the same manner on the replacement alternator.
Figure
Figure 4
Nearly all 3 Series alternators have a brush/regulator assembly in the rear that can be easily removed and replaced (blue arrow). Remove the brushes and inspect them carefully if your alternator is not working well. If the contacts are short in length, they are worn and need to be replaced. If they are long (as shown in the photo), you probably have some other internal problem with the alternator that’s causing it to malfunction. Replacing this regulator assembly is a good step to take prior to spending money on a rebuilt unit.
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Comments and Suggestions:
Spotcoolerman Comments: Pelican, We have a 2006 530XI with 41,000 miles on it. We have owned the car since new and it has had each and every service performed on the vehicle as required. Over the past six weeks, the battery light periodically comes on .... and then goes away. There does not appear to be any logic to the timing - either in length that the light stays on - or when it appears. Sometimes the light appears when we start the car and stays on for 3-10 minutes... other time, it only appears when we are driving down the road and will at times stay on for less than 30 seconds and other times will remain on for many minutes. This never impacts the performance of the vehicle. It always starts, operates as it should and when we have the battery tested, it is at full charge. The alternator appears to be working properly. We have taken it in twice to Sears we have a Die Hard Battery to have it checked for a bad battery and each time we are told everything is fine. Any suggestions of potential sources of the problem?
December 12, 2014
  Followup from the Pelican Staff: I would bet the charging system has an issue. I would perform a charging system test to determine if the alternator can supply the correct voltage and amperage. - Nick at Pelican Parts  
tkwonger Comments: I removed the Bosch 140a alternator from e36 m3 98. Trying to transfer the pulley over to a new remanu alternator, but for the life of me I cant figure out how to take off the pulley on this alternator. Do I need some special tools
December 8, 2014
  Followup from the Pelican Staff: You shouldn't. Can you share a photo of the pulley? - Nick at Pelican Parts  
CCQ25 Comments: I have a beautiful trouble free 2007 328I. I bought it nine months ago and must admit from day one it probably had the slightest hesitation, or slow start. I say probably, because after driving the car to run an errand it took three turn overs o start back up. Four hours later, another three turn overs to start. The next morning NOTHING! Had it towed to the dealership thinking it was a battery, when I was told it was a bad starter, and battery was fine. $900.00 later I must admit the car literally purrs, and starts within a millisecond! My scare is that everyone at work says once a starter goes, the alternator is next. Is this true? My apologies for being such a newbie, but do I know need to start setting money aside for a possible new alternator just because the starter went bad? Thanks so much in advance!
December 6, 2014
  Followup from the Pelican Staff: No. That is not true. The only relation is the age of the parts. - Nick at Pelican Parts  
Pedro Comments: Hi i have a 1999 bmw 323i stick shift and every time i come off a gear into neutral and the rpm drops back down to idle my dashboards lights seem to lose brightness but get bright again really quick and also my headlights seem to dim but then come back up to normal any suggestions on what might be causing this ???
November 24, 2014
  Followup from the Pelican Staff: First check that the battery and charging system are OK. if there are and the problem persists, check if holding the throttle slightly open remedies the issue and report back.- Nick at Pelican Parts  
Alonzo Comments: Also you said to start at the coolant temp sensor, well it so happens that I replaced that a few weeks ago..
November 20, 2014
  Followup from the Pelican Staff: Which one?

The battery light is on due to the low RPM and engine being close to stalling. You will need to check engine parameters to see what is going on when you start the engine. Is the coolant temp wrong, is fuel delivery in spec, etc. Once you perform some tests, you will have better direction. - Nick at Pelican Parts
 
Alonzo Comments: Follow up with my recent post, I have a 2002 BMW 325i.
November 20, 2014
  Followup from the Pelican Staff: Ok, got it. - Nick at Pelican Parts  
Alonzo Comments: When I turn my car on from a cold start my car starts to down rev and eventually it turns off. I have to do this about 5 times to get the car warmed up or else it turns off while i'm driving and each time the battery symbol on the dash comes up in the color red. Once I get the car warmed up and around the middle of the temperature gauge the car runs fine. I just replaced the battery not too long ago so I'm assuming the alternator is just on it's way out. Even though when the car is warmed up and I've been driving, the voltage is where it needs to be around 14.2. Any ideas on what it might be?
November 20, 2014
  Followup from the Pelican Staff: You didn't mention what vehicle you have. Could be a coolant temp sensor issue. i would start there. - Nick at Pelican Parts  
Traw Comments: I have an 85 325e and have a new alternator and replaced all the bulbs in the instrument cluster, but when turning the key over the Batt light will not light up and the volts at the battery terminals go down after cranking until the battery slowly drains over the course of 4-5 days/50ish miles. I have fiddled with the connection to the Batt bulb at the back of the cluster with the key turned over and cleaned the connection thoroughly to no avail. Any help??
November 9, 2014
  Followup from the Pelican Staff: Is there voltage coming out of the wire for the battery bulb at the back of the cluster? - Nick at Pelican Parts  
Georgecz Comments: Hi I have a 2002 BMW 325i M54my mechanic said that I have bad bearings in my alternator causing the slight squeal I hear. It is still working but he said it is going to stop at some point. Can I just replace the bearings or just get a reman alternator? If a reman alternator - which one? I see a 90A and 120A - I also see one with an air duct and one without? confused - last 7 of VIN -nj19383. Any help would be great!
November 4, 2014
  Followup from the Pelican Staff: You will need a new alternator. Yours will likely have the cooling duct as well. Give our parts specialists a call at 1-888-280-7799. They can help you find the right part.
- Nick at Pelican Parts
 
eric Comments: my just purchased 2008 e64 gives many faults /transmission fault, dynamic driving, brake ...etc./ at starting after overnight park. Restart after idling about 10 min everything gets normal. nothing bothers me again until next day. battery sticker shows 1 month old, looks like rebuilt one.
November 3, 2014
  Followup from the Pelican Staff: If the vehicle starts OK and isn't cranking slow, the battery is likely not related to the issue. There could be a fault in the ABS system causing alight that goes away once that amount of time passes. I would start by checking the vehicle for fault codes. If multiple systems are not working properly, fault codes will be set. This will be your best bet when diagnosing.
- Nick at Pelican Parts
 
Shawzi Comments: 2007 328i had a few battery replacements. Low Battery indicator comes on everytime I start the car. After driving for 10-15 min and stop and start it again the problem go's away. However when sitting for a few hours the problem still persists. Low battery power. Any ideas? Thanks
September 24, 2014
  Followup from the Pelican Staff: I would star by checking the starting and charging system. You could either have a weak alternator or a faulty battery. - Nick at Pelican Parts  
johan Comments: Clicking noise from air adjuster on inlet manifold
September 4, 2014
  Followup from the Pelican Staff: I'm not sure what you are adjuster you are referring to. Is the check engine light on? - Nick at Pelican Parts  
kagura454 Comments: The lettering on my dashboard is all wack and isn't readable. The battery and alternator have both been replaced but I still have a red battery sign showing. Also when I'm sitting idle at a red light for too long my car's temperature will start climbing towards the red, but as soon as I start driving it will climb back to normal.
Any suggestions on the causes / possible fixes ?
September 3, 2014
  Followup from the Pelican Staff: The instrument cluster and overheating issue are two separate problems. The cluster needs to be repaired or replaced: http://www.pelicanparts.com/BMW/techarticles/BMW-3-Series-E46/79-BODY-Removing_Your_Instrument_Cluster/79-BODY-Removing_Your_Instrument_Cluster.htm

I would check the coolant level and bleed the system if needed. Also check the cooling fan.
- Nick at Pelican Parts
 
Johan Comments: Hi I have a 2007 323 and what I have noticed is that after a few minutes after starting there is a clicking noise coming from the alternator and it starts to charge. Can you please help.
September 3, 2014
  Followup from the Pelican Staff: I would inspect the drive belt and tensioner. - Nick at Pelican Parts  
joe Comments: I have a bmw 321 and replaced alternator and starter still no charge whats the problem?
August 5, 2014
  Followup from the Pelican Staff: Could be the power cable to the back of the alternator. - Nick at Pelican Parts  
PapiChulo Comments: I have a 1997 328i and my alternator failed. Since I was replacing it I figured I would upgrade from an 80 amp to a 120 amp both are bosch however the 120 amp alt has a plug on the back with no ground and the 80 amp has power and ground but no plug. Is there a way to use the 120 amp alt in my car?
July 22, 2014
  Followup from the Pelican Staff: Was your vehicle normally equipped with the 120? If so, you may have to replace the wiring harness as well to get it work. - Nick at Pelican Parts  
Bella Comments: I have a 2006 BMW 325i I replaced my alternator when I turned on the car it was idlying high. I had the battery tested and it is fine what could be causing the the revving of the engine when at a stop?
July 18, 2014
  Followup from the Pelican Staff: I would check if a vacuum hose or intake air boot is not connected. - Nick at Pelican Parts  
Eric Comments: Hi!
- 2001 330ci, M54. -
Last night coming home from work 35mi, 1 hour, got the battery light, first intermittent, then steady, then it went out "Lucky!" I thought. Almost home the radar detector frizzed out, then the ABS/Traction lights flickered on.
Grabbed my meter out of another car as soon as I got home and got 9.5 volts !!!. Charged her up overnight, everything worked this morning, but she's not charging.
My questions:
1. Is there a known mechanism by which the warning light first goes on, then turns itself off, even though the alternator has not started charging again? I've never had this happen in any other car.
2. What, exactly, is the teleologic explanation of the functions of the two smaller alternator wires? I know that one is directly from the "RUN" circuit of the ignition switch, and the other goes through the DME to the cluster, and then to the warning light, but what is the purpose of each? If this is an internally regulated alternator, then neither one of them is a field wire, though one may be an exciter or voltage sensor wire. If one turns on the warning light when its voltage drops, creating a ground path, then what is the significance of the connection through the DME?
Just trying to understand the intended function so that I can properly troubleshoot.
Thanks!
July 11, 2014
  Followup from the Pelican Staff: Trouble shooting is easy.

You will need power to the large wire.
Term 1 is hot with the key in run position
Term 2 is for charge indicator, as charging system voltage exceeds battery voltage, the warning light goes out.

- Nick at Pelican Parts
 
Mike Comments: i have a 2003 320i my battery kept going flat over night.. i replaced the battery same issue kept happening.. i jump started battery car started let it sit for a bit went for a drive and it had no power or acceleration and struggled up hills any ideas what is wrong?? alternator?? cheers
June 15, 2014
  Followup from the Pelican Staff: It does sound like a charging system issue. I would check the charging system. If it is OK, check for a parasitic draw. Here is a list of the specifications: http://autotechdiagnostics.com /?p=185
Once you confirm there is a draw. You will have to isolate the circuit with the draw. Then determine which components on that circuit is causing the draw You can isolate by removing fuses. be sure to have all the latches on the doors and hood closed (pin switches) so the vehicle will sleep during testing. If it wakes up, you will have to wait until it goes to sleep again. - Nick at Pelican Parts
 
Harry Comments: I have a 2000 X5 4.4i. Some months ago my wife left the lights on. The car would not start. We had it towed to a garage. They replace both battery and alternator. Now, three months later, all the yellow dash lights are on and the car intermittently will not start. Any ideas?
June 12, 2014
  Followup from the Pelican Staff: Does the engine crank when you try to start it? Is there clicking or nothing? - Nick at Pelican Parts  
vaderdjm Comments: I have a 90 735iL with a 140 amp alternator. My battery light started to come on the other day, followed by other warning lights that indicated I was dropping voltage. Finally the car died. Checked the battery, dead. Recharged and started testing components. Had the alternator tested, 14.2 volts. Re-installed the alternator and the battery light came on. Checked voltage at exciter lug- 7vdc. Checked instrument cluster, 12v going in to the test circuit, 7 coming out. The bulb is good. Tested alternator by applying 12vdc to exciter leg momentarily, charging circuit started and 13.2v achieved. Any ideas what could be causing the low voltage? I would rather not add a push button to my dash just to start the alternator.
June 9, 2014
  Followup from the Pelican Staff: You could be missing 12 volts at the alternator field wire. Have you checked that? If so, it could be a fuse, wiring issue or the charge indicator circuit. - Nick at Pelican Parts  
balebu Comments: HELP !! Alternator, ignition switch, or ?

Here are the symptoms,tell me what you think:
Car: 1997 BMW 528i, E39 engine, 292k miles.

- 3 times during past 4 months, starter failed to engage on first key turn.
- airbag light has been on for past year.
- 2 days ago, while driving for 1hr, the Battery light came on. Voltage was 12.4 and dropped to 11.9 at my destination - Car sat for 2 days. 5 minutes after starting - at night - the dash dimmed, gauges for speed, rpm, etc went low, though I was traveling on highway.

The engine manual trans did not feel like it wanted to stall. No bucking or jerking.
Headlights failed, dash lights almost failed, then, after about 15 minutes...THE HEADLIGHTS AND DASH LIGHTS JUMPED BACK ON BRIGHT!!!
BTW, this happened after coming off a bumpy clover leaf onto a different highway. did something move? Ignition key, battery in trunk, or just bad voltage reg in alternator?

The lights stayed bright for the next hour. Battery voltage showed and remained 14.4 - 14.5 volts! What gives?

What part or parts is/are faulty? Any help would be more than appreciated.
May 31, 2014
  Followup from the Pelican Staff: You could have a loose connection at the battery or a faulty alternator. I would voltage drop the battery cables and load test the alternator. - Nick at Pelican Parts  
britt Comments: hi, i have a 2008 bmw 328i. i drove my car home on empty with 22 miles left until i needed to refuel. I was going to get gas the next morning... turns out i wake up get in the car , try to crank it and it will not start. All the lights, dash board, and radio still work. We tried to jump start it and nothing happened. we re-charged my battery there had been a drag in it... recharged completely and still no crank. what do you think it could be ?
May 29, 2014
  Followup from the Pelican Staff: If the vehicle isn't cranking it could be a faulty starter. I would voltage drop test the cables to the starter. Then check for the start signal to the starter solenoid. - Nick at Pelican Parts  
Curt Comments: 70k miles of problem free driving with my bought new in 2002 325iT until lastnight.

All dashlights illuminate and limp home mode with my auto trans stuck in higher gear.

Noticed charge voltage is over 16v and strong smell of batter acid... battery and cable test fine...

It is possible to order and change regulator to fix high voltage charge?
May 22, 2014
  Followup from the Pelican Staff: Not that I know of. I believe only the complete alternator is available. Give our parts specialists a call at 1-888-280-7799 and they can help figure out which part or repair kit you need.
- Nick at Pelican Parts
 
Steve Comments: Hi. I have a 2002 E46 318I. I have had the alternator recently replaced and it is charging okay. Also a new battery. But the battery warning light remains on. Any ideas? Thanks.
April 30, 2014
  Followup from the Pelican Staff: We don't have your vehicle in the US, so I don;t have the wiring for it. Here, the blue wire, terminal 2 goes to the charging indicator. This should be battery volts with key on engine off, then rise to charging system voltage with the engine running. As voltage goes up, the bulb goes out. If it doesn't go up, the alternator may be faulty. - Nick at Pelican Parts  
JOEY Comments: i have a 1994 BMW 325i and yesterday i tried replacing the 80 amp alternator. i noticed the bottom of the pully shaft on the old alternator was petruding from the housing of the alternator and makes contact with the bottom of the pully so when the pully spins the inside of the alternator rotates as well. On my new alternator the same spot on the pully shaft is recessed into the housing of the alternator so there is no contact with the pully. when i tightened down the pully it just tightened to the housing and wasnt spinning the inside components of the alternator. my question is ... is my new alternator defective? or is there and adjust somehow to raise that shaft so the pully makes the proper contact and spins the alternator?
April 16, 2014
  Followup from the Pelican Staff: You may have a different brand or production date production alternator. Where did you source it? I would check for an available pulley kit or spacers. - Nick at Pelican Parts  
Mombez Comments: I have a bmw e38 7series, battery light is on, mechanic says there is no power going to the alternator so I have to check why there is no power going there before buying a new alternator. Might have to call an electrician but its expensive. any ideas what it might be?
April 11, 2014
  Followup from the Pelican Staff: Check the back of the alternator. if the main lug has no power, the wire to the battery may be faulty as it is a direct connection. if the smaller wires have no power, check fuses F22 and F23.- Nick at Pelican Parts  
oz Comments: i have a '95 525i e39 that before it died on me, the dashboard letters were half written and flickering as if the cars wasnt receiving enough energy or charge. I never had an electrical issue with the car except for this, so im assuming it must be the alternator who gave up on me. My question is will an alternator from a '00 528i e39 fit my car? thanks
February 25, 2014
  Followup from the Pelican Staff: No it will not. - Nick at Pelican Parts  
blayne1107 Comments: I have a 2008 328i and replaced the battery 2 weeks ago. Then, last week had to replace the alternator. Now the idle is off and the temperature gauge is acting crazy and shutting down the acceleration intermittently. I took it to the stealership and they said the alternator was overcharging and I needed to replace it so I did used another mechanic and it is STILL doing the same thing. Any suggestions on what might be causing this?
February 21, 2014
  Followup from the Pelican Staff: Could be a faulty DME. I would start by checking the DME for fault codes. If the system is not working properly, a fault code will be set. This will be your best bet when diagnosing.
- Nick at Pelican Parts
 
wolf Comments: 2003 z4 does not start after I parked pushed start ok , switched of to see if it starts again. Yes , next day started normally .parked it , later again no start , had to push .all other electrics strong and dash lites normal , what can it be
February 20, 2014
  Followup from the Pelican Staff: Could be as simple as a faulty starter. I would check for the crank signal to the starter when the fault is present. - Nick at Pelican Parts  
ben Comments: I took my 535 xi for oil change and the shop noticed that I had a leak in my vacuum lines which they replaced..The next day I drove from CT to NY then stop for a snack then got back in the car it won't start. Headlights and instrument panel lights came on but car won't start.. I had it towed to the shop but they can't figure out what's wrong with the car.. can anyone help please
February 19, 2014
  Followup from the Pelican Staff: I can't help without knowing what is missing from the system when you are trying to start it. When your engine doesn’t start you’ll want to check the basics. Check spark, fuel injector pulse and pressure fuel, volume and quality. Are there any fault codes? Once you figure out what is missing, it will be easier to diagnose.
- Nick at Pelican Parts
 
Mike Comments: hello i just bought a 2002 nmw 325i, only has 92k on it an after driving 200 miles i lost power. car was still running just no acceleration. dealership said was a siod on alternator. alt was pumping 16volts out to battery. could this be the only problem. its my 1st beemer and i really love it just hoping dont have problems like this constantly. please help
February 17, 2014
  Followup from the Pelican Staff: 16 volts is too high, the alternator may be faulty. I would start there. - Nick at Pelican Parts  
Rob Comments: Hi, I have a 1995 318i with 295,000km on it. Today I was driving and noticed my car stereo was cutting in and out and when I turned off the heater fan it fixed it. Then the check engine and ABS light came on. Then the stereo quit and the heater fan was slowing down and lights were dimming. I realized it must be alternator as I have a new battery however no warning light came on for that? I've checked the belt and it turns. Does it sound like an alternator even though no warning or something else? Thanks
February 16, 2014
  Followup from the Pelican Staff: It could be. I would perform a staring / charging system test. See this tech article for tips on how to test your charging system: http://www.pelicanparts.com/BMW/techarticles/BMW-3-Series-E46/56-ELEC-Alternator_Replacement/56-ELEC-Alternator_Replacement.htm - Nick at Pelican Parts  
Antonio Comments: Hello i have a 2002 e46 325i that doesnt charge my battery. Ive replaced the alternator twice thinking that maybe one was bad as well as a new battert, but car only reads 12.7 volts when running. I also noticed that the 2 pin connector harness to the alternator only has a single green wire coming out of it rather than having the blue wire other e46 owners describe. Could this be the source of my charging issue or should i seek another possibility? Thank you.
February 11, 2014
  Followup from the Pelican Staff: You should have a green and a blue wire, both of which are supplied with battery positive when the key is ON or in the START position. - Nick at Pelican Parts  
DAB Comments: Can a faulty alternator or poor alternator replacement job lead to a water pump failure? A dealer put in a remanufactured alternator and soon after the 2002 325ci was making a whining/squealing noise? Then, on the highway, the battery light came on, the car overheated and the steering went out. And they say the water pump issue is unrelated?
February 6, 2014
  Followup from the Pelican Staff: Not that I can imagine. Sounds unrelated. - Nick at Pelican Parts  
MTI Comments: I have a bmw e30 1985 model with 155400kms on the clock.The car stalled while I was driving it I found out that the alternator was not charging the system so I had it repaired. the alternator came back from repairs and only worked for a day,it currently doesn't charge again.what do you think caused the failure again.could there be another problem in the system that is causing failure?
December 22, 2013
  Followup from the Pelican Staff: I would check the alternator connections. Voltage drop test the power and ground feeds. If they are good the alternator is likely faulty, again. - Nick at Pelican Parts  
leeemery Comments: Got a e46 2000, had battery & altonator check & all is fine. Car still having trouble starting, all lights on dash still work, electric windows etc but still no turnover unless jump started. Something else is draining battery but what???
December 19, 2013
  Followup from the Pelican Staff: Is the battery charged when you try to start it? I would load test it. If so, there may be a bad connection to the starter or battery. Perform a voltage drop test on the cables from the battery to the starter motor. - Nick at Pelican Parts  
tommygun Comments: on a 97 bmw 328IS automatic, it appears that the pulley on the alternator is squealing makes a lot of noise when in gear can you replace just the front pulley to fix the sound, cause the alternator is working fine any comments to what to do?
November 30, 2013
  Followup from the Pelican Staff: Check the alternator belt to make sure it is not aged, cracked or dry. Replace the belt if necessary. If the alternator pulley looks gklazed (from all the sliping and squealing), use fine sandpaper to scuff its belt contact surface. If all else fails, give our parts specialists a call at 1-888-280-7799 and they can help figure out which pulley kit you need. - Nick at Pelican Parts  
roland Comments: i have a 98 528i alternator went bad so i replaced it started car read 13.4v drove the car it lost power and trans went into failsafe shut the car off and had to jump it to get it to start tested volts again read 11.88 removed alternator had tested 'bad' got a different one installed volts still read 11.88 to 11.69 tested grounds 'good' and my sterio comes on normal but stock amp doesnt i have no sound
November 25, 2013
  Followup from the Pelican Staff: Focus on the charging system issue. I would check that the circuit to the alternator is good. You should have battery volts on all the wires with the engine running.- Nick at Pelican Parts  
Stew Comments: Changed the alternator on my 2007 328i. Now when driving the engine occasionally looses power and the engine overheat light comes on, then it will regain power, any thoughts?
November 23, 2013
  Followup from the Pelican Staff: The water pump is an electric motor. Yours might be intermittently seizing pulling down the voltage. I've had to change a few water pumps in my time. - Kerry at Pelican Parts  
Hjlmoody Comments: Hello, just wondering if I can use an alternator from a 2003 320d on my 2002 model. Do bmw manufacture alternators to fit on pretty much all of their cars?
November 18, 2013
  Followup from the Pelican Staff: That depends on production date. From 9/2001 to 9/2002 the alternator is the same. Then from 9/2002 to 6/2006 it is the same. - Nick at Pelican Parts  
Bryan Comments: Thanks Nick...but actually I was not clear. I will be installing an aftermarket incandescent warning light. I want to add a resistor as a "fail safe" in case the warning light burns out. So the bypass circuit will include a warning light with a resistor installed in parallel.

My manual on the BMW says it has a resistor as a fail safe in the stock cluster...but if it does I sure do not see it.

My other question...say I determine 100 Ohm is the correct resistor size...how does one determine how many watts are appropriate?

Thanks for the help.

November 13, 2013
  Followup from the Pelican Staff: 100 ohm sounds high, I would think it will be under 4.

I have not done what you intend to myself. However when I use a resistor for electrical system testing in automotive circuits, lets say to take the place of a component, I use 1 to 3 watt 5% resistors. - Nick at Pelican Parts
 
Bryan Comments: I am deleting the stock gauge cluster on a 1990 M3 track car, and installing a digital dash.

I understand this will prevent the alternator from charging, unless I complete the charge warning light circuit with a resistor.

My question: What resistor size would be appropriate for this? I imagine the rating is not too critical, but I know relatively little about resistors and thought some knowledgeable advice would be a good idea.

Thanks!
November 12, 2013
  Followup from the Pelican Staff: If you are looking to replace the instrument cluster bulb circuit, the easy way to do it would be to measure the resistance of the bulb in your cluster. Then use a resistor with a similar rating and resistance. - Nick at Pelican Parts  
Quest Comments: 2002 BMW 330i bat came on yesterday went out last night, came back on this morning and stayed on for about 15 mins half way to work. Bat light went out for about five mins and has been on since. Took the car to my mechanic, he tested the alt. it tested around 11v he said that he would check the bat and all the connections but he thinks it's the alt. your thoughts?
October 21, 2013
  Followup from the Pelican Staff: Sounds like an alternator to me, make sure your battery is fully charged when you have the alt installed. If not you could damage the new alt.
- Nick at Pelican Parts
 
KCC Comments: Hi I have a 1997 328i. About a month ago I replaced my alternator with a remanufactured Bosch unit. Yesterday while driving I noticed the dash lights were dim, radio totally no power and turn indicators not working. I immediately pulled over and turned off the car. When I tried to restart the car wouldn't start. So I left the car there overnight. Today I could start the car and managed to drive home. The automatic transmission light came on. After I got home I turned the car off for an hour. I turned on the power and transmission light disappeared. What could be the problem here? My battery is also about 5 years already
October 13, 2013
  Followup from the Pelican Staff: It sounds like the alternator is not charging, was the battery fully charged before you started the car with the new alternator? I would test the alternator and battery.
- Nick at Pelican Parts
 
Marco Comments: I have a 2003 BMW 525. Battery was replaced recently but keeps going dead. when running my battery voltage reads low at 10.5V, would this indicated a bad alternator? belt seems fine.
October 7, 2013
  Followup from the Pelican Staff: It sounds like the alternator is not charging, you should have over 13.5v at idle with loads on. I would replace the alternator and recharge the battery completely.
- Nick at Pelican Parts
 
Dave Comments: I have a 1994 BMW 325is. The dash lights including the air bag, battery, ABS, and the radio cluster suddenly comes on while driving at highway speeds. The vehicle looses power for a brief moment and then the entire dash goes black. The car then "resets" and runs normal. any ideas?
September 23, 2013
  Followup from the Pelican Staff: Start by checking your power and ground connections from the battery. It seems like you might have a power or ground supply problem.
- Nick at Pelican Parts
 
wavecruzer79 Comments: Hey Guys, I have a 95 M3. After I put in a new Kenwood radio using the easy harness the radio shuts off when I put on my headlights. I have HID conversion lights and never had this issue before the radio. I've already replaced the alternator. Still having the issue. The battery never dies, No issues starting either. If I turn on the lights slowly, I.e. parking lights, wait a few seconds then lights. Its normally fine.

Any Ideas?

Thanks
September 18, 2013
  Followup from the Pelican Staff: I would remove the radio and back probe the connector and see what is missing when it is not working, power, ground and so on. When you figure out what is missing trace it back to the cause. - Nick at Pelican Parts  
cam Comments: i am having an issue with my 1999 528i touring. ithevcar sometilmes turns over, biut most of the time does not. the airbag light is on and the led for the radio is out of wack. i have got a new ignition switch, and a new battery. next up im going to try the alternator then if i have to have the starter replaced. any ideas?
September 15, 2013
  Followup from the Pelican Staff: I would check to see if the starter is getting power when you try to start the car, if it is the starter is faulty. The LED's in the radio are not related, the radio will have to be replaced, and you will have to scan the car to see why the airbag light is on.
- Nick at Pelican Parts
 
Lauren Comments: My 1974 model 2002 keeps stalling at slow speeds and stops. The alternator, points and carburator have all been checked. The battery mount is rusting out the battery is not completely stable, sliding but not in contact withe ground. could this issue to be fixed soon be related to the stalling problem?
September 8, 2013
  Followup from the Pelican Staff: If the battery positive cable is touching ground it could cause problems, You could have a vacuum leak, inspect the engine for a cracked intake boot, vacuum line or leaking gasket.
- Nick at Pelican Parts
 
The Chief Comments: Something weird happen today after I replace the front rotors on my 2005 525I. During the test drive the car was braking fine but I notice that my headlights would dim a little. This is the first time I have encounter this. What could have gone wrong?
September 6, 2013
  Followup from the Pelican Staff: I don't think they are related. Check you battery voltage while the car is running, should be above 13.2V if it is not turn on all electrical loads in the car, a/c, rear defroster, blower motor, headlights, radio, if the battery voltage starts to drop below 13V your alternator is starting to fail. Check you power and ground connections and if they are ok, replace the alternator. - Nick at Pelican Parts  
Patrick Comments: can a faulty alternator cause transmission fail safe error. BMWe39 car ran perfect without notice of trany problems. Shop diags needs new trany. Hard to believe mechanical without any warning.
September 3, 2013
  Followup from the Pelican Staff: Low voltage can cause the trans to go into fail safe , but should not damage the trans, could be that the trans is just worn out.
- Nick at Pelican Parts
 
328IS/1998 Comments: A brand new battery was dead after sitting for a few days. Testing at the auto parts store says I have a bad stuck open diode and need a new alternator. Is it possible to replace the diode or should I just purchase a new alternator?
August 27, 2013
  Followup from the Pelican Staff: Your best bet is to change the whole alternator.
- Nick at Pelican Parts
 
Ann Comments: I have a 2003 525i BMW and is having problems with the electrical system I've been told. I have a new battery, had it turned up, had a leak that was fixed and something is still draining the battery. When I let it sit for a week because I have another vehicle the battery drains and I'm unable to start the car. Can it be the alternator? Any suggestions?
August 26, 2013
  Followup from the Pelican Staff: Sounds like the car is not "going to sleep" this is a common problem that can be caused by many things, you have use a low current amp meter to measure the draw on the battery while the car is off, should be less than 50mv. Anything greater than that will kill the battery. If you do find that there is a draw, you need to start pulling fuses one at a time until the draw goes away, that would be the circuit that is affected, then check whatever is on the circuit. It can take hours to find the problem.
- Nick at Pelican Parts
 
Candis Comments: Hi. I have a 2007 BMW 328i, and yesterday I came out of the store to it not starting. All of the interior lights, windows, sunroof and even headlights come on... but when I put the key faab in the slot and push to start, it won't "turn over". Tried to jump the battery, and that didn't work. What do you think it could be?
August 13, 2013
  Followup from the Pelican Staff: Could be a control module, the electric steering lock, the key, or the starter. You should have the car scanned with a factory scan tool and see if there are any faults stored.
- Nick at Pelican Parts
 
jorge1229 Comments: i have a 745i and i put the key in and all the light go on but the car wont start what can i do? what do you think is happening how can i fix it
August 12, 2013
  Followup from the Pelican Staff: Could be a control module, the key, or the starter, it would be best to have the car scanned with a factory scan tool to see if there are any faults.
- Nick at Pelican Parts
 
Rizi Comments: Thanks Nick for the feedback.. it was the fuel pump
August 10, 2013
  Followup from the Pelican Staff: Thanks for the follow up. We appreciate it.
- Nick at Pelican Parts
 
peter Comments: 2007 328i won't start makes no sounds. after towing to shop it will start every time, then if it sits over night will not start or make any sounds. Also will not respond to electronic key.Just dead no lights horn or able to shift into neutral. Started replaced battery replaced. What's the issue?
July 31, 2013
  Followup from the Pelican Staff: There could be a problem with the electric steering column lock, scan the car with the factory tool and see what faults are stored,
- Nick at Pelican Parts
 
david Comments: Hi i have a 93 bmw 325 is i turn the switch to turn on the car but it wont start all my bash lights up but nothing i replaced the alternator and starter but still the same.....
July 29, 2013
  Followup from the Pelican Staff: Check the condition of the battery make sure it is charged. Check you battery cable connections. Also take a look at the ignition switch.
- Nick at Pelican Parts
 
manic Comments: I have a 2003 330CI. I replaced the alternator about 4 months ago and everything has been working fine. The other day my battery light came on again. checked the alternator it went bad. My mechanic says it got HOT. The vent is cleared from debris and I live in Alaska so its not warm here. Anyone else seen this issue or am i just lucky to have had the alternator fail. replaced with Bosch parts
July 25, 2013
  Followup from the Pelican Staff: If the battery was not fully changed when the alternator was installed the life of the alternator can be shorted drastically.
- Nick at Pelican Parts
 
Casey Comments: I've a '93 318is, and the last week has been weird. For about 2 weeks, I had intermittent battery light flickering on the instrument cluster at idle, which went away as I gave it some gas.

Last week, the car wouldn't restart after stopping- radio and gauges worked, starter wouldn't turn. I replaced the battery as it was about 6 years old, and all was well for 4 days. Today, though, I was getting ready to leave work, and the same problem recurred.

Lights/gauges/radio all work, but turning the key to the start position results in nothing. No sound of the starter turning. I'm testing the battery now. Could it be an alternator?

Also, I noted that the trunk light was very, very hot when I was pulling the battery- hot enough to have notable heat in the lens, and the bulb burned my thumb pretty nicely. Could a drain there be the problem, if this isn't shutting off?
July 21, 2013
  Followup from the Pelican Staff: Sound like the alternator is faulty, replace it and charge or replace the battery. Check the trunk light bulb and make sure it is the correct wattage.
- Nick at Pelican Parts
 
Bmw Comments: Hy, i have 318 mod 2000, after running the car about 20min the gearbox indicator go blank in the dashboard and i cant switch between automatic mode and tiptronic mode and it make some ticking noise, can you help? Thank you
July 20, 2013
  Followup from the Pelican Staff: Sounds like there may be an issue with the trans control module. I would start by performing a full vehicle scan to check for fault codes. - Nick at Pelican Parts  
sabhu Comments: Bmw 318i e46.. Lights do n0t w0rk at the same time, if the left side is working then the right won't work... First thought it was the bulbs but after I had changed them it wa the same... Its also showing a light with all doors open and all lights on... Help

July 16, 2013
  Followup from the Pelican Staff: This vehicle has a light switching center control unit that controls the lights. Sounds like yours is acting up. This module has scan tool capability - Nick at Pelican Parts  
Rizi Comments: Hi..yesterday My 2004 325ci would crank and start but died off after 10 to 15 seconds later. I jump started it and it run fine but with some cricket noise under da hood. Battery voltage is 12-13v b4 starting and 14-15v after starting. But Today it wouldnt start again. Any suggestion please??
July 10, 2013
  Followup from the Pelican Staff: Try tapping on the starter while someone turns the ignition key. Sounds like you might have a bad starter - Nick at Pelican Parts  
xaytoven Comments: can low voltages cause irratic iddling on my 94 740i
June 23, 2013
  Followup from the Pelican Staff: Yes, low charging system voltage can cause a lot of electrical problems. - Nick at Pelican Parts  
Laban Mosi Comments: I own a 2000 BMW 328i E46. I heard a whistling noise from the alternator and being somewhere I couldn't get specialist attention I opted for a Toyota mechanic who removed the alternator and replaced the bearing. One thing that I must also admit that it took them 6 hrs to redo the serpentine belt since they didn't know how. Since then my car indicates that the battery is low and can't even start the engine. What could be the problem?
May 15, 2013
  Followup from the Pelican Staff: You could have a faulty battery or alternator. I would perfroma charging system test to determine which it is.- Nick at Pelican Parts  
Lisa Comments: I replace the motor and tranny on my 1995 BMW 325i the car started and turned off now it won't do anything what can it be
April 25, 2013
  Followup from the Pelican Staff: Check for spark, injector pulse and fuel pressure. You could have aloose connection or a bad ground. - Nick at Pelican Parts  
RAJENP Comments: I HAVE A 1994 E36 M3 THAT NEEDS EITHER A REGULATOR/ COMPLETE VALEO ALTERNATOR
YOU QUOTE PART 12311744564
BUT MY LOCAL BMW QUOTE 12311403936
MINE HAS 2 CONNECTIONS ON REAR
THE E46 HAS 3 CONNECTIONS
CAN I REPLACE MINE WITH THE ONE YOU QUOTE
THE SPECS ARE THE SAME
mail me and I wills end you a picture of the rear
April 7, 2013
  Followup from the Pelican Staff: Give our parts specialists a call: 1-888-280-7799 They will be able to assist in you finding the correct part. - Nick at Pelican Parts  
drayko Comments: I have a 2001 BMW 325ci, I have replaced the battery and replaced the alternator 3 times and I'm still getting the same issue... It's a valeo alternator that pushes out 120 amps but each alternator I put on is only pushing out 30 amps. I can not figure out this problem... Can someone please give me a suggestion.
March 30, 2013
  Followup from the Pelican Staff: How and when are you testing the amperage? Is the charging system warning lamp illuminated? If you suspect the aperage is low, check fuses F30 and F34 in the interior fuse panel.- Nick at Pelican Parts  
Ben Comments: I have a 2003 z4 and I just replaced the starter, then 1 week later the battery light came on. Is there a correlation between the two or is this just coincidence?
March 28, 2013
  Followup from the Pelican Staff: Recheck all your connections. Did you disconnect the vehicle battery when the starter was replaced? - Nick at Pelican Parts  
Nathi Comments: Please help alternater doesn't want to charge even replaced with a new battery when the car idles and remove the terminal it shuts off but there is no warning from the dashboard, car E46 318i 2002
March 21, 2013
  Followup from the Pelican Staff: Check fuses F30 and F34 in the interior fuse panel. Fuse F34 send power to the charge warning light.

Also, never disconnect a battery while your engine is running. Damage to the vehicle electrical system can occur. - Nick at Pelican Parts
 
arius Comments: I have a 1993bmw 325i it will run for 20 minutes then the dash goes out and the car dies we just but a new alt. On and check all the ground I am lost any help would be great.
February 17, 2013
  Followup from the Pelican Staff: Have you checked the ignition switch? If it is faulty, the vehicle could lose power like you are describing. - Nick at Pelican Parts  
agus Comments: my car is BMW318i, e36 m43. why indicator alternator at instrument cluster light ON, can to reset ?
February 13, 2013
  Followup from the Pelican Staff: You could have a charging system problem. I would perform a charging system test. - Nick at Pelican Parts  
frazzled Comments: having charging problems with a 1987 528 e, 64,000 miles. brought it home and battery died, bought a new batery and 2 days later it died, checked alternator out put it was 12.5 volts, battery voltage disconnected is 12.8. bought new alternator and same problem out put at batery was 12.6. took alternator to a reputable rebuild house and it checked out good put out about 100 amps under load, not the alternator, resistance from negative side of battery to alternator bracket was low, could this lack of chargingbe something in the dash related to the charge light? or does this car need a separate ground from negative battery to alternator case?
January 21, 2013
  Followup from the Pelican Staff: The alternator does need a good ground. I would check the ground using the voltage drop method, resistance is not a good way to check it.

The charge indicator bulb goes out when charging system voltage exceeds battery voltage. If it is staying on, therei s either a bad connection or the alternator is not charging. - Nick at Pelican Parts
 
Dan Comments: 2004 325Ci sorry the alternator is new too. actually tried two new alternators and battery.
December 27, 2012
  Followup from the Pelican Staff: See my reply to your other question. - Nick at Pelican Parts  
Dan Comments: I have a 2004 325Ci. The alternator will not charge the new battery. The field coil small wire shows 8.6 volts. should it be 12 or does the computer regulate this voltage?
December 27, 2012
  Followup from the Pelican Staff: Voltage is regulated inside the alternator.

Here are a few voltage specs for you.

The large wire goes to the battery, this should read what the alternator is currently charging at.

Terminal 1 should be battery voltage, from fuse F30 7.5 amp
Terminal 2 will be battery voltage witht he connector unplugged, this goes to the charge system indicator. As alternator volatge exceeds the voltage on this circuit, the charge indicator goes out.


- Nick at Pelican Parts
 
johnny Comments: developed an electrical issue in a 2002 318i touring automatic which I would really appreciate if anybody could offer an opinion on
Problem showed itself initially with dashboard warning lights either flashing on and off or coming on and staying on ABS, traction, handbrake, airbag. Stereo and/or heating have also dimmed and then shut down.
if you stop and restart car lights normally go out.

Yesterday lights came on and automatic gearbox shut down into safe mode, no power from engine to drive but engine still running. When I turned off engine and tried to restart, dashboard lights went out but when tried to restart car it wouldn't turn over at all just a clicking noise.

Jump started the car from a power pack - no issues, swapped out battery, no lights came on and car drove home fine.

Where I am kinda stuck is when i put a multimeter on original battery it showed battery was ok, i put the battery back in car and it reads 14.7 when car is running and all seems to be working/driving fine. Certainly problem seems to be intermittent and wonder any suggestion. many thanks
November 15, 2012
  Followup from the Pelican Staff: You could have a faulty alternator. I would perform a starting and charging system test. Load test the battery and the alternator. - Nick at Pelican Parts  
gmyatko Comments: Regarding the initial comment that the battery will gnerally only leak acid if overcharged is a bit too general. We were tracking our E36 M3 and found acid all around, thinking the battery went bad after a spin. Found out there was a vent hole that looks like it should or could have a line attached to it. Bottom line is the battery was fine, but leaked enough acid around to cause concern.
November 8, 2012
  Followup from the Pelican Staff: Thanks for the additional Info. We appreciate it.
- Nick at Pelican Parts
 
i need help Comments: i have a 2007 bmw i sometimes the do not start
September 30, 2012
  Followup from the Pelican Staff: Does the engine crank when the problem occurs? I need more information to be able to help you.
- Nick at Pelican Parts
 
HUGO Comments: BMW M3 E46 2004 THREE ISSUES APPEARED AT ONE TIME.FOLDING PASSENGER SIDE MIRROR NOT OPERATINGDRIVER SIDE OK RADIO NOT OPERATING AND INDICATOR ILLUMINATION ON DASH NOT SHOWING ALTHOUGH INDICATORS ARE WORKING/FLASHING.
September 24, 2012
  Followup from the Pelican Staff: I've seen this a bunch of times. If your fuses are good, the ignition switch may be faulty. - Nick at Pelican Parts  
Frustrated Comments: I have a 2004 645 CI I have had it for 5 years it has spent more time parked in the garage and at the dealer than on the road. I am scared to drive it. Everytime I take it after about 50 Kilometers the radio starts kicking in and out the entire dash then goes black the abs light flashes then it shows a picture of the car on a lift next think you know it dies. I have have brought it to the dealer 5 times once a year and then I park it so far 3 batteries the cables to the battery have been replaced and today the amp to the radio it happened again on the way home from the dealer, can you help.
July 24, 2012
  Followup from the Pelican Staff: There will be fault code associated with the lights that are illuminating. The fault codes will direct toward the root cause. Do you have the codes the dealer was able to retrieve when they serviced it? Could be a power problem with CAS module. - Nick at Pelican Parts  
Tim Comments: i have a 92 318i e36 the alternator is basically crooked how do i fix something like that? do i replace the bolt and brackets theat hold it in place? where do i find that?
June 7, 2012
  Followup from the Pelican Staff: The bushings are likely faulty. I would replace them. - Nick at Pelican Parts  
Macer Comments: I attached my a different battery to my 2003 Z4 3.0 and now when i connected the new battery, wipers go on without key in the ignition and alternator gets hot to the touch in seconds any advice???
May 24, 2012
  Followup from the Pelican Staff: The new battery could be shorted inside or you could have a incorrect connection somewhere.
- Nick at Pelican Parts
 
roofer57 Comments: i have a 2003325ci battery lite was on when i started the car after i was driving the car approx 4 miles radio died out kept driving the car all dash lites came on and car eventually stalled car sat for 2 hours eventually started drove car for approx 30 miles without a problem?????
March 6, 2012
  Followup from the Pelican Staff: You could have an intermittent problem with the alternator. I would load test the charging system. - Nick at Pelican Parts  
jomby Comments: Hi, i have E46 320D 2003, on the tho points aroun the motor i have 14.2v but in the trunck on batery they is only 12.6v. The alternator lamp is turning on some times. Tryed another battery and same result.
Any idea?? Thanks!!
February 11, 2012
  Followup from the Pelican Staff: Check the connections for all of the battery cables, you are going to have a poor connection somewhere.
- Nick at Pelican Parts
 
Spennykaz Comments: Hey Wayne, iv got an 1984 318i, my battery light stays on even with the car off, it idles like crap, but it's charging I think I disconnected the power wires from it while running and my idle was perfect, however my headlights are getting dimmer and my stereo won't turn on, the battery light is off with the car off now, however, when running, my park brake, brake fluid and battery light come on. Help? I installed a new rectifier and it's been doing it ever since, the stator had 3 wires connecting it to the rectifier and the new rectifier has 4 hoops to solder the stator to... I soldered them to where it looked like they were supposed to go. I couldn't find any diagrams and I'm at a loss
February 3, 2012
  Followup from the Pelican Staff: Do not disconnect the battery while the car is running. You can damage electrical components, including the alternator. It sounds like it is time for a new alternator. - Nick at Pelican Parts  
redfiyah Comments: My 1995 bmw 318 i keeps losing charge. I have to jump it everyday. The alternator checks as good, this is a brand new batteryactualy the second one because I took the first one back because I thought it was bad/old...how can I find out why the battery dies when sitting for 1 night?
January 30, 2012
  Followup from the Pelican Staff: You may have a parasitic draw. You'll want to monitor the draw on the battery when the vehicle is asleep. Here is a list of the specifications: http://autotechdiagnostics.com /?p=185

Once you confirm there is a draw. You will have to isolate the circuit with the draw. Then determine which components on that circuit is causing the draw You can isolate by removing fuses. be sure to have all the latches on the doors and hood closed (pin switches) so the vehicle will sleep during testing. If it wakes up, you will have to wait until it goes to sleep again.- Nick at Pelican Parts
 
kennysugar Comments: My 650ci convertable battery aint charging anymore yet it doesn't show battery sign on the dashboard, am suspecting my altenator is that the fault?
January 25, 2012
  Followup from the Pelican Staff: The alternator could be putting out just enough voltage to keep the light off but not charge the battery. Measure the voltage while running, it should be over 13.3v with some electrical loads on.
- Nick at Pelican Parts
 
tomas Comments: Problem is and has been for some time, that when I turn on the parking lights I don't have to turn on the headlights to cause it, the parking lights suffice to produce it all dashboard lights dim by about three/fourths. they become so dim, especially, for the tach and speedo and gas and temp gauges that they are essentially unreadable. any thoughts? suggestions? could bee the regulator not regulating well? realy with built up resistance? I'm flummoxed. thanks!!
December 29, 2011
  Followup from the Pelican Staff: Hmm, have you tried turning the headlight knob - that typically changes the brightness of the dashboard. When you turn the lights on, they are set to automatically dim on the dash. This is adjustable - the exact method varies depending upon the model of car.- Wayne at Pelican Parts  
Hornblower Comments: I forgot to tell you that I have a 1989 BMW 325i convertible.
December 21, 2011
  Followup from the Pelican Staff: Thanks, got it. - Nick at Pelican Parts  
Hornblower Comments: Your instructions would probably cover 95 percent of the problems. I experienced alternator "failure" due to a bad connection in my instrument cluster. It so happens that when you turn the ignition switch to run or start 12 volts are feed thru the instrument cluster C1 pin 14 connector to power the charge indicator light in parallel with 10 ohm resistor in case bulb burns out and then feed out via C1 Pin 16 to power the alternator field coil. This provides the voltage to create the magnetic field to generate the voltage when the alternator is rotating. A bootstrap circuit provide voltage via steering diodes from the alternator stator to the field coil after the alternator is running then providng a counter voltage to turn off the charge indicator light. In my case, the C1 connector, thru corrosion and old age, created an open circuit that did not allow the 12 volts to go to the field coil. Reinserting new C1 Pins 14 and 16 female pins in the C1 connector fixed the problem. No BMW "experts" could fix this problem. After replacing 3 good alternators and 3 batteries replacements I uncovered and fixed the problem.
December 21, 2011
  Followup from the Pelican Staff:
Thanks for the Info. We appreciate it.
- Nick at Pelican Parts
 
harryo Comments: 96 bmw318is auto when ignition off no horn no brake lights bmw brake switch installed new .
horn and brake lights work when ignition on or car running
December 12, 2011
  Followup from the Pelican Staff: The brake light switch only receives power when the key is ON. Your symptom sounds normal. - Nick at Pelican Parts  
elio Comments: oups i forgot to tell u my BMW is 2006 Model
November 25, 2011
  Followup from the Pelican Staff:
Thanks for the Info. We appreciate it.
- Nick at Pelican Parts
 
elio Comments: hi i just bought a BMW 325i two days ago;
today i tried to open it it wasn't opening.so i opened the door using the small key.
when i tried to enter the key and turn on ignition it was no activating. but all the lights is functioning wich proove that the batterie is still ok.

What do you think the prob is??
November 25, 2011
  Followup from the Pelican Staff: There might be a problem with the electric steering column lock, scan the car with a factory scan tool and look for faults in the ELV.
- Nick at Pelican Parts
 
bimmer1992 Comments: Ater replacing the alternator 105 amps original 80 amps on my BMW 316i 1992 model, the siren and tones when arming/disarming or using the panic botton on the laserline 996V3 alarm do not work.
Any ideas? As before replacing the laternator everything worked perfectly
November 10, 2011
  Followup from the Pelican Staff: I don't have any experience with the laserline 996V3 alarm. I would locate the fuses for the alarm and see if they are OK. - Nick at Pelican Parts  
firstbimmer Comments: hey.. last night in my 1995 325i..car stero speaker stop playin then the abs light started flashing.. then came back then it ran fine ..then it happen again then it completely died. then i let in seat for a while and turn back over .
October 15, 2011
  Followup from the Pelican Staff: I would check the battery and alternator. You may have a low voltage issue. - Nick at Pelican Parts  
nixta003 Comments: Hi there i won a 1993 November release 318i e36 awesome car love it but i am having issue with my instrument cluster the whole thing went out while is was driving even the odometer went out none of the dials work. I have taken the cluster out using instruction from the net and checked for Batteries but there are none i wanted to make sure i checked all the fuses blade fuses and they seem fine, when i disconnected the battery in the boot and reconnected it the odometer came back on actually all the dash lights came back on now they are all still okay and working but the dials are not no speedo no fuel gauge and no temp gauge however i did notice that when i reconnected the battery the fuel warning light has come on and stayed on is there anything you can suggest i also try before i go looking for another one to buy, im enjoying working on my BMW its the first car ive ever worked on, awesome site guys, look fwd to any suggestions you may have
October 14, 2011
  Followup from the Pelican Staff: You may have a faulty instrument cluster. I suggest running a system test using a BMW scan tool. - Nick at Pelican Parts  
Josy Comments: I just rebuild my altarnator put it back on and still not charging. Took it back off and had it tested and they say it way good. put it back on and still dosent work. Does anyony have any idea what I sure check nexts?
October 1, 2011
  Followup from the Pelican Staff: What year and model is he car, sounds like you are missing the control voltage for the regulator.
- Nick at Pelican Parts
 
Rebecca Comments: Hi there, just bought a bmw 318i 1999 E46 and found that some idiot cut the wiring to the alternator and taped the blue and green wires together to fit a lower amp alternator for an E39 into the car. Can you tell me what the green and blue wires to the alternator are used for? Also, I have replaced the alternator, connected it to the battery, and have also replaced the battery, but still the car dies on me after driving it for about 1 hour, as the new alternator is not charging the new battery. There must be a voltage drop somewhere, but I don't know where to look? Could this be a cabling problem from the alternator to the starter motor? Your help would be greatly appreciated.
October 1, 2011
  Followup from the Pelican Staff: My wiring diagram shows two wires to your alternator. The red wire is the main battery lead. The blue wire is the ignition feed that goes through the charging system warning light. - Nick at Pelican Parts  
Blunder Comments: My 2003 325i does not start and gives only the ABS and seat belt light on dash when key is turned. The engine gives a vibe like something is wrong with the alarm system

I have only one key and has to use it manually to open and start car
September 27, 2011
  Followup from the Pelican Staff: Is there no check engine light? What is the temp gauge doing? Check this link for some helpful information. http://autotechdiagnostics.com /?p=213 - Nick at Pelican Parts  
Blue Comments: I have 95 318is bmw that over heated on the highway I added water and it seems that the water was exiting out of a hose in the top center of the engin my brother plug both ends and when I made it home it died on me now ive replace the part the car wont turn on what do I do.
August 27, 2011
  Followup from the Pelican Staff: The battery might be dead, check to make sure is it charged. Also check to make sure the motor still spins over by turning it by hand.
- Nick at Pelican Parts
 
eztuner12 Comments: Hi!
When do I know is time to change the voltage regulator?
Any symptoms I should look for or notice!
Thx
August 19, 2011
  Followup from the Pelican Staff: When you charging voltage is not consistently about 13.2v there might be a problem with the regulator.
- Nick at Pelican Parts
 
tom Comments: I have 530XI 2006, I don't understand why my generator fan kicks in when I started the engine and it would run for several minutes, and there is not indicator light on my dash board. Please advice, and thanks in advance.
August 10, 2011
  Followup from the Pelican Staff: You are hearing the electric air pump running, this is normal, the pump is part of the emissions system.
- Nick at Pelican Parts
 
Alex Comments: I have an '87 325es and it was marking 18-20 volts with the engine off it cranks but wont start, so i changed the alternator and the system still reads 18-20 volts, engine off. Last I checked and no power is getting to the dme when key is on Run, but it gets power at Acc. Could this be a short?
August 7, 2011
  Followup from the Pelican Staff: Your voltage numbers are high. I would recheck them, Battery should be around 12 volts. If your are missing power to DME but get it with key ON, it may be a bad ignition switch. - Nick at Pelican Parts  
eztuner12 Comments: Hi Wayne
First I have to congratulate you for the fine team force you have at the shop. I have placed a couple of order thru your e-shop and it has been a superb experience ļ
My issue this time is, that any time my radiator primary electric fan turns one all the lights on the car dims. This happened when the car is in idle @800RPM even the A/C cools less at this point. Once I reeve the car up to @ 1000RPM or more everything goes back to normal. Battery seems to be on the right voltage and it keeps charged always. I removed the Alternator an OEM Valeo 80 Amp and I checked the brushes for wear but they seemed to be ok. The alternator is 15 years old but the car has only @ 23,400 run miles since I got the car new. Do you think that the alternator regulator may be causing this lights dim scenario even if the brushes look well?
Perhaps any other part I should check, go for a new regulator or new alternator perchance? Can I go with the Valeo 105 Amp you have on your catalog?
My car is 1997 e36 M44 318is VIN # AS71156. Just in case you need the info to recommend me a part or what I should do.
Thank you
August 3, 2011
  Followup from the Pelican Staff: This sounds like a bad alternator. Monitor charging system voltage while loading the circuit. Load it by turning on your blower motor and headlights. If voltage doesn't hold, the alternator is faulty. i would replace it. - Nick at Pelican Parts  
mike Comments: For the past two months I've been changing my fuel tank and steering rack. After I completed the job with the batt disconnected I started her up and apart from the rough idle she ran ok got a bit better when hot... Then the lights went out and the car died and wouldn't crank. I jumped it and she runs fine, put a charged batt in and runs fine, until it loses charge and dies. My car ran just fine before I changed the fuel tank and steering rack. How did the altinator die?????!!And I've checked the engine ground wire
July 10, 2011
  Followup from the Pelican Staff: The alternator is not charging, it could just be from sitting and corrosion on the brushes.
- Nick at Pelican Parts
 
joshdude Comments: Hi I have a 2003 325 ci, new alternator and battery. Now here is a little preview of how I found out I was having a problem. I had my radio on the other day and it kept cutting out every time I used the turn signal. Upon further investigation I only had 12.2 to 12.8 volts running at the battery and the same at the alternator. Now when I lift the hot lead off the battery when car is running the voltage jumps up to 13.2 to 13.6 volts. Tried this with two different batteries with same result 12.2 to 12.4 with battery connected and running and 13.2 to 13.5 with car running and battery not connected.
Thanks for reading josh
July 8, 2011
  Followup from the Pelican Staff: When you disconnect the battery the regulator will try to up its output, it will no be able to sustain that voltage level for very long,
- Nick at Pelican Parts
 
sideeffekt Comments: Sorry, car was an 87 325es, with original Bosch alternator. The original alternator grounded and was metal on metal at all mount points.
June 15, 2011
  Followup from the Pelican Staff: Thanks, got it. - Nick at Pelican Parts  
sideeffekt Comments: 'Auto parts store Checker/O'Reilly is selling alternators with electrically isolated mounting holes - there is a rubber grommet separating the mounting holes from the rest of the alternator, preventing the bolts from grounding the alternator like they should.'

I ran into this same problem with an Ultima remanufactured alternator from Checker. Solution was running an 18gauge wire as a ground from a bolt that sticks out a little further on the back of the alternator, up to back side of the tensioner bracket between that and the alternator mount. Battery was too dead to start before I ran the ground, afterwards, it started right up.
June 15, 2011
  Followup from the Pelican Staff:
Thanks for the Info. We appreciate it.
- Nick at Pelican Parts
 
shawn Comments: I have a 94 318i, i have a problem with pulsating lights which i believe could be the voltage regulator, am i correct? Secondly my biggest problem is that when i start my engine cold, the car runs fine, but as soon as i warms up it starts to sputter....once the rpms get around 2000 it runs great.....could this also be linked to the pulsating lights or the voltage regulator....or just the ignition coil?
June 6, 2011
  Followup from the Pelican Staff: This sounds like a bad alternator. Monitor charging system voltage while loading the circuit. Load it by turning on your blower motor and headlights. If voltage doesn't hold, the alternator is faulty. i would replace it. - Nick at Pelican Parts  
Tiffany Comments: I have a 1999 323i bmw. My alternator went out and i let it sit for about 2 weeks before replacing it. I started it occasionally and it started fine. I let it sit for a whole week without starting it at all and it started but would not stay idold. I replaced the alternator and it still wont stay idold. What is it and what do i need to do to fix it.. Please help
June 5, 2011
  Followup from the Pelican Staff: Will it stay running if you lightly press on the accelerator pedal? If so, the problem could be in the idle control circuit. - Nick at Pelican Parts  
Easyas123 Comments: How cam I regrease or replace the front bearing on alternator for a 1993 325i?
Noise is not noticeable, but sounds dry and feels worn when spin by hand.
I extended the life by replacing the regulator/brushes.
June 4, 2011
  Followup from the Pelican Staff: You can remove the bearing, then find one the same size. Other tahn replacing the alternator, that is your only option. - Nick at Pelican Parts  
Melissa Comments: I have a 1999 BMW 328i and I recently changed out the alternator as I was originally told the alternator was bad. Now I was haveing the same problem with having to get a jump everytime I shut off the car, I went back and had it the alternator tested again and it said my regulator was bad. Where is the regulator and how do I replace it?
May 25, 2011
  Followup from the Pelican Staff: The regulator is built into the alternator. It bolts to the back of it, sometimes you can get a replacement regulator only.
- Nick at Pelican Parts
 
Victor Comments: I have a 2006 M3 convertible, at high rev the battery light comes ON, during idle its fine, I also noticed when I rev high when engine is cold no battery light, so I see it only when high reving and engine hot, may this be alternator problem?
May 6, 2011
  Followup from the Pelican Staff: I would check the belt and the belt tensioner, sounds like the belt could be slipping when it is hot.
- Nick at Pelican Parts
 
Rodman Comments: Ok I have a 1990 with an 87 325i engine in it. The belt snapped off and I didn't notice until the next day when my cars lights and raideo started to dim and cut off. I replaced the belt and it still wouldn't hold a charge. Replaced the battery drove fine for a day then did the same thing with lights and radio. Replaced the alternator twice and it still won't hold a charge. I've checked the entire charging system and I have connection every where. I have been working on it for three weeks and I'm stumped also checked all grounds any help would help thanks
April 12, 2011
  Followup from the Pelican Staff: I would check the charging voltage at the battery to start. This will tell you if the alternator is attempting to charge the battery. I would also triple-check all the grounds using an ohm-meter. Measure the resistance between the battery negative terminal and the housing of the alternator - should be zero. - Wayne at Pelican Parts  
Charles Comments: I have a BMW 318i...the wiring was cut to the alternator....The ? is which wires go where?
April 6, 2011
  Followup from the Pelican Staff: Sorry, I don't have a wiring diagram handy (you didn't mention what year your car was). - Wayne at Pelican Parts  
tay Comments: Okay, for three days i've been trying to replace my 1995 530i alternator, and have failed to even remove the old one. I'm getting deeper and deeper into the disassemlbly of surrounding components, and am frustrated with the difficulty of what should be an easy job. This is the first time I've ever seen an alternator mounted on the bottom with it's own air intake. Can post pics if helpful. Any advice would be appreciated, thx!
March 9, 2011
  Followup from the Pelican Staff: I'm going to copy this question to our forums and send you a link. If you can go there and post some photos, perhaps we can help you decipher this. - Wayne at Pelican Parts  
Al3xe36 Comments: Could i replace the alternator on my 1995 318i its 80 amps to a 140 amp one. Also the reason I'm replacing it is because someone told me the bearing is going bad so it whistles is that true?
March 8, 2011
  Followup from the Pelican Staff: In theory, the alternator should only supply as much current as is drawn by the system. In other words, if you have an 80 amp unit and your draw is only 40 amps, then you can use anything above 40 amps and it will be fine. People typically install a higher amp alternator when they are installing a big stereo system, or higher power headlamps. So yes, installing a higher output unit should be fine.

On some more modern cars they will sometimes trigger an alternator lamp when you install a higher amp unit as they are not expecting the alternator to be charging above it's expected level. - Wayne at Pelican Parts
 
den Comments: I replaced the voltage regulator on my '03 325xi, now the car will not start,the starter is cranking but it wont fire? There was no problem before replacing the VR and I'm wondering if there are fuses related to the ignition system that should be checked where they are located? Everything else was reconnected. Thanks
March 6, 2011
  Followup from the Pelican Staff: I'm going to post this question over to the forums, and perhaps you can add some more details there. Why were you replacing the regulator, what was wrong with the old one? Did you disconnect the battery prior to working on the car? Did you check all the fuses to make sure that they were still functional and not blown? - Wayne at Pelican Parts  
frustrated Comments: I have a 1995 318i. I have a battery drainage problem. Its a brand new battery and the alternator was tested 4 different times at 4 different places. It tested out fine. The battery light is on, then the alternator modular light turns on then the car dies. Left overnight, it starts works fine but can die anytime. what could be wrong?
March 2, 2011
  Followup from the Pelican Staff: It could be just about anything, but I would start by checking the ground connections. Measure the resistance from the engine to the chassis - it should be very low. Verify that your ground strap is in place and fastened properly (maybe remove it and clean it up with a wire brush?) - Wayne at Pelican Parts  
josh Comments: hi was wondering were i can get brushes for my 2003 325ci
alternator. thanks
March 2, 2011
  Followup from the Pelican Staff: Unfortunately, the newer-style alternators are not user-repairable (they don't sell the parts separately). You have to buy a whole new unit. - Wayne at Pelican Parts  
Scott1981 Comments: I have an 04 325ci and red battery light keeps coming on from time to time. The car still runs and after I drive it for 5 mins or so, I turn off the car and turn it back on and the light stays off for a few days until it decides to come back on. I don't notice a loss in power either. What could this be?
February 27, 2011
  Followup from the Pelican Staff: I'm not sure - it could be the battery, or it could be the alternator. I would probably replace the battery first and see if that fixes the problem. If the battery is original, it may be time to replace it anyways. - Wayne at Pelican Parts  
Vladae46 Comments: Hi,
The challenge I am having with my alternator is noise, lots of whining noise. It charges fine, no issues. Sounds like a bearing that is shot. Can I replace the bearing only?
2001 E46 325Ci.
Thanks.
February 13, 2011
  Followup from the Pelican Staff: Sorry, no, the bearings are not available separately. The best recommendation I have is to remove the alternator and have it checked at a repair shop that can possibly regrease the bearings or at the very minimum confirm that it is indeed the alternator that is making that noise. It can be difficult to tell with 100% certainty that the alternator bearings are making the noise (and not perhaps another component in the engine). - Wayne at Pelican Parts  
John Comments: '90 BMW 325is died while driving. First lost wipers, dash lights/gages, radio, heater blower then finally engine cut out. Suspect bad alternator. After getting it home I hooked up jumper cables to another car and jumped it note: battery is very low on charge. Ran fine until I removed the neg cable - died within a few seconds. I'm thinking that the alternator died and I was running off battery until charge ran too low. Does it make sense to check anything else like voltage regulator or does this sound like a bad alternator? Looks like I could take the voltage regulator/brush assy out without removing anything else and check it first to save possible unneccessary work. Is there an easy way to check it? Also, if I buy a new/reman alternator will the voltage reg come with it I think it would, right?. Thanks.
February 7, 2011
  Followup from the Pelican Staff: With issues like these, I like to start with the cheapest and easiest thing to fix - the battery. I would recommend testing and/or replacing the battery to make sure that it can hold a proper charge. Also check the voltage coming out of the alternator - if the voltage is too high (let's say 15-16 volts or higher), then it may be overcharging and damaging the battery (which causes it to fail more rapidly). On the new alternators, the voltage regulator is indeed built-in to the unit. - Wayne at Pelican Parts  
Richard Comments: Hi.
I'm looking for all grounds wires on my 1997 e36 318is. I look up "project 85" as suggested on the article but nothing comes up on project 85 page regarding ground wires locations.
Can you please tell me where can I find all ground wires on my car model?
Advanced thx....
February 2, 2011
  Followup from the Pelican Staff: There are something like 30 or so ground points in the car. I'm not sure exactly what you're looking for, or trying to accomplish? - Wayne at Pelican Parts  
Sakarii Comments: I have a 3 Series 2000 BMW with 150k miles. When I got out of work I got stuck in snow for about 30 minutes and when I arrived home I got stuck once again for another 30 minutes. While switching gears from reverse to drive on my drive way I noticed the alternator/battery light turn on and now I cant turn my tires in any direction. Any ideas what it could be? Battery? Alternator?
February 1, 2011
  Followup from the Pelican Staff: Hmm, are you sure it's the battery lamp, and not the transmission lamp? The transmission lamp is a little gear that lights up. Seems that would be more likely. Showing a battery lamp after what you described here, I don't have any clue as to what would have caused that... - Wayne at Pelican Parts  
den Comments: I'm ready to replace the VR Valeo on my '03 325xi wagon auto.
Please confirm if this can be done without removing the alternator?
January 22, 2011
  Followup from the Pelican Staff: I'm pretty sure that you need to remove the alternator to reach the voltage regulator. On your car, I'm pretty sure that the voltage regulator is located on the back of the alternator. - Wayne at Pelican Parts  
rubz Comments: hi there, i have a 318i m-sport. Whilst im driving the battary light comes on and soon after that my hand break and ABS Light comes on. Most of the time the lights go after i rev the car but now the car jst cuts itself off i then have two jamp start in order for it work.
January 20, 2011
  Followup from the Pelican Staff: This certainly sounds like an alternator problem. Or, it could be a battery problem. I would check the battery first, and make sure that it's operating properly, then move on to replacing the alternator. Also check to make sure there is a good ground connection between the alternator and the battery. - Wayne at Pelican Parts  
Eric Comments: How do you disconnect the wiring from the back of the alternator? I've tried pulling and prying, but am afraid I will break something. 91 318i
January 12, 2011
  Followup from the Pelican Staff: You just need to get in there and maneuver it out. On that car you should be able to reach in from behind with the proper tools (might need some angled wrenches). - Wayne at Pelican Parts  
Gremible Comments: On a 1983 533i a new battery started dying overnight. Connecting an ammeter between the battery and chassis with the key off I found something was drawing 3.5 Amps! It took awhile to isolate it to the alternator. With the car running, the voltage was 13.5V so I thought the alternator was O.K. I took it out not so easy on this car and O'Reilly's tested it as good, but near the bottom of the spec. I replaced it with a rebuilt unit and the current drain was down to 200mA another issue. I suspect one of the six diodes 3Øwas shorting giving a leak path to ground but still allowing enough current to charge some from the other two phases.
November 26, 2010
  Followup from the Pelican Staff: Thanks for the Info. We appreciate it.
- Nick at Pelican Parts
 
Matt Comments: I wanted to follow-up one more time in case anyone else ran into problems like this. Running a large ground wire off of one of the mounting bolts did not work!! It turns out that the auto parts store Checker/O'Reilly is selling alternators with electrically isolated mounting holes - there is a rubber grommet separating the mounting holes from the rest of the alternator, preventing the bolts from grounding the alternator like they should. With the help of a friendly employee, I found my old alternator the core was still there and sure enough the bolt holes were continuous with the rest of the alternator case. With luck on my side, I removed the brush/regulator from the back of both alternators, and put the brush/regulator from the "new" alternator onto the "old" alternator. With the new brush/regulator the old alternator PASSED when it was tested!! The brush/regulator was the only bad component, so my recommendation is try buying one of those separately and install it if your alternator is bad - it very well may be the problem. The store refunded my money for all the hassle over 2 days of work and I left with a repaired old alternator. Installed in and finally it works, this is solve once and for all!!!
November 21, 2010
  Followup from the Pelican Staff: Most alternators are indeed wired with a separate ground connection, so this seems odd to me, although I'm not sure which car you're working on. Bottomline, check the resistance between the alternator and the battery ground prior to replacing the alternator or voltage regulator. - Wayne at Pelican Parts  
Matt Comments: For the reference of anyone who reads this, and may ever be troubleshooting an alternator, I solved my problem. Even though I cleaned the mounting bracket with a wire brush and everything looked shiny and conductive, the alternator was still not grounding properly. I ran a wire 4 awg battery cable from the alternator to the chassis to ground it, and IT WORKS. Nice to solve these long drawn out problems!!!

One more note: I looked into it and the capacitor is NOT critical to the function of the alternator. I believe it is just to reduce noise. Hope this information is helpful.
November 20, 2010
  Followup from the Pelican Staff: Thanks for the feedback Matt. I tell *everyone* troubleshooting an alternator problem that they should check the resistance from the alternator to the battery ground first, and make sure there is low resistance there. - Wayne at Pelican Parts  
Matt Comments: My girlfriend left the lights on all day on my 1987 BMW 325i. It was dead, and when trying to jump start the car, the engine would die whenever the cables were removed. The batter then didn't seem to be holding charge so I got a new one and installed it. The car started and ran but the alternator was not charging the battery Voltage decreased from 12.6 to 12.0 volts instead of increasing to 13.5 with car on.

I took the alternator off and had it tested. The store employee told me it was bad and then sold me a new alternator. I put the new alternator on and was still having the same problem, not charging the battery. On the off-chance that the new one was bad, I took it off again and had it tested. It passed. I cleaned the bolts and mounting brackets and reinstalled the alternator hoping to solve a bad ground problem. No luck. My engine ground strap looks fine and has negligible resistance. I had a glance at a wiring diagram for the car and of the two wires going to the alternator the larger wire runs to the starter and is hot at all times shows same voltage as battery car on or off. The smaller wire runs to the ignition switch and has no power unless the ignition switch is turned on, at which time it shows about 0.5v less than the battery.

The pulley and belt are fine and spin at the proper speed when the car is on. I checked the resistance on the wire between the starter and alternator and there was negligible resistance. I even pulled a working battery from another vehicle to see if somehow my new battery was bad new battery is fine, just no charge being supplied from the alternator. I can't think of what else to check and am really frustrated. The fuses are fine... wiring looks fine to me. If I start it the engine will die if the negative battery cable is disconnected, which I thought indicated a bad alternator, though the alternator passed the testing.

There is a small black case with a short wire and plug on the back of the alternator which I transferred from the old alternator to the new. I believe it is a capacitor, but I'm uncertain if or how it affects the alternator performance. Could it be bad, and be causing the alternator not to work? What other possibilities are there? Could the new alternator be bad even though it tested good once??? I am so frustrated, any advice would be truly appreciated. -Matt
November 20, 2010
  Followup from the Pelican Staff: First I would voltage drop test the battery cables and engine ground. if it is good, the new alternator could definitely be bad. Monitor charging system voltage while loading the circuit. Load it by turning on your blower motor and headlights. If voltage doesn't hold, the alternator is faulty. I would replace it, again. - Nick at Pelican Parts  
Jimmy Comments: I have a 2004 BMW 325I, alternator idle is 13.8 before driving everyday, then idle voltage dropped gradually after driving. If I drive a little long, idle voltage drops below 13.0 no charging and drain the battery. I already replaced factory belt, pulley, battery and alternator is ok, however, this problem still not solved. Even strange thing is the battery warning signal never on. Can anybody help me
November 14, 2010
  Followup from the Pelican Staff: If the voltage is 13V, it should be still charging a 12V battery. If you are simply measuring voltage using the dashboard gauges, then you might have an issue with your gauge - these are typically not very accurate. Also, when the car heats up, the resistance in the wiring changes (becomes more resistive). If you have corrosion on some components (like a ground strap perhaps), then the addition of heat may change the grounding effects. This is just a guess of course, but it sounds like your problem may be heat-related. - Wayne at Pelican Parts  
willow Comments: I DRIVE A BMW 2002 318i the battery light came on then there was loss off power, had my car towed to bmw dealership,they replaced the alternator, the next day went to drive it battery light came on again and lost power for a moment, took it back they did a diognostic test couldnt find anything, drove home. Next day did same thing. Should things be going on like this just after having a major service done on vechicle,and why would my car still be playing up.
November 6, 2010
  Followup from the Pelican Staff: Although shops like to opt for more expensive work, I typically replace the battery first when I'm having problems like these. Modern batteries tend to act a lot more quirky than the ones in the old days. - Wayne at Pelican Parts  
Jimmy Comments: Can I replace a 150 amp alternator with 120 amp alternator. I really can not find a 150 amp one locally.
October 26, 2010
  Followup from the Pelican Staff: Yes you can, although the battery may wear down if you have a big stereo or a lot of other electrical drains on the system. - Wayne at Pelican Parts  
L.T. Comments: I unknowingly replaced my alternator after hearing a loud whistling noise in that area. It ended up being the idler pulley that needed replacing. anyways everything was fine for months then all of a sudden my battery light kept turning on and off sporadically. There's no loss of power or dimming of lights, but every once in a while my car will not start. The battery is less than 6 months old. I've also recently replaced the drive belt. Am I supposed to tighten the belt more than the tensioner does? any ideas???

Sorry. Never included that it was a 2000 323i sedan
October 22, 2010
  Followup from the Pelican Staff: The belt is self-tensioning. It may be a problem with the tensioner that you replaced, or the belt too. Also, make sure that the grounding between the alternator and the battery is good - check it with a multimeter. When installing the new alternator, the ground connection may have become corrupted. - Wayne at Pelican Parts  
haris Comments: i have BMW 318i 2002 with 120A valeo alternator, and its having problems so i have to change but when i bought new its coming with 2 pins, but mine is having single pin connector. so what is the best solution?? is there any plug converter is available for this item? or i have to look for the same alternator?? but the problem this alternator is very hard to find i think even there is no any part number sticker on the old alternator. so please write a suggestion.
thanks
October 18, 2010
  Followup from the Pelican Staff: I would get the same alternator. I wouldn't try to retrofit something to your vehicle. - Nick at Pelican Parts  
Robert Comments: Looks sounds like my Wife's 2005 325Ci needs an alternator pulley not idler. Bought one from the local dealer and should get some time later this week. I've relaced the idler and tensioner pullys a couple of years ago. Without being able to see adeqately at this point, even with the airbox out, can you tell me thype and size of drive for the retaining bolt? And, are there any tricks to loosening the bolt?

Thank you in advance,

Robert
October 11, 2010
  Followup from the Pelican Staff: This tech article will get the job done:

http://www.pelicanparts.com/BMW/techarticles/BMW-3-Series-E46/56-ELEC-Alternator_Replacement/56-ELEC-Alternator_Replacement.htm - Nick at Pelican Parts
 
haris Comments: thanks for your quick reply. but have you ever seen such a problem??? because of this recently i changed the battery, but it was not helping. did u check the video? but when i start the second time there is not any kind of problems. but are u sure is it with voltage regulator or alternator?
October 6, 2010
  Followup from the Pelican Staff: Could also be a grounding problem. Weird electrical problems are tough to track down and diagnose, as you have discovered! - Wayne at Pelican Parts  
haris Comments: My bmw 318i 2002 2.0 is showing high voltage above 17v in cold starting, even my dash lights are flashing in my first start, but if i start again after 2 min the voltage will be showin 14v to 14.3v. so what will be problem of this???
Please see the video..thanks
http://www.youtube.com/watch?v=-UjSAXbGvGo
October 5, 2010
  Followup from the Pelican Staff: That seems quite odd, I would guess it has something to do with the voltage regulator going bad? - Wayne at Pelican Parts  
Daniele Comments: Hi,
I have a 323ci that never had problem, but last night it turned on, i moved it for 5 feet and then it lost RPM and turned off. Now it does not turn on. The battery is ok, the oil level is ok... I am kinda scared: bmw parts are so expensive!!!!
September 23, 2010
  Followup from the Pelican Staff: See what codes the car is putting out, it will probably show you a few: http://www.pelicanparts.com/bmw/techarticles/Mult-Code_Reading/Mult-Code_Reading.htm - Wayne at Pelican Parts  
Rob Comments: Hi, I own the 101 projects book and it has been of great help! However, I finally have a problem that I can't figure out what's causing it. My 1989 325i died while running last night after driving on some high elevation gravel roads. The car showed the usual signs of a failed alternator... lights dimmed, and then the car finally died got it started with a jump, died 5 minutes later. The battery light never came on it does in accessory mode so the bulb is not burned out and I had both the alternator and battery tested and they turned out fine although of course the battery was drained. Any ideas what's causing me to lose power?

thanks,
Rob
September 18, 2010
  Followup from the Pelican Staff: Hmm, it *does* sound like a classic alternator problem. When you had the alternator tested, did they check the voltage regulator too? That's important as well. Other than that, perhaps your ground strap is loose. The ground connection between the engine and chassis should be minimal, otherwise the battery won't charge. Check the strap and then maybe the wire harness after that (clean the battery terminals too). - Wayne at Pelican Parts  
Mike82 Comments: 97' 328i Hydrolic belt tensioner.
There is a "Cricket" noise coming from under the hood, I replaced all belt bearings and the noise is still there. The noise seems to be coming from the alternator area. If I turn on the headlights or A/C, the noise gets louder. Could this be a an alternator problem?
September 18, 2010
  Followup from the Pelican Staff: Yes, it might be an alternator issue. I would take the alternator out and have it tested - they can check both the output and the bearings inside the alternator. - Wayne at Pelican Parts  
overmyhead Comments: i have a 92 318i runs fine alternator tested good but wont charge battery...got new battery n same deal when running shows around 12.5v but as soon as u turn car off it wont restart n battery shows 6v
September 7, 2010
  Followup from the Pelican Staff: Check to make sure your ground strap is properly connected. This is probably the source of your problems. Without the strap, the alternator can't complete the circuit and will only slightly charge the battery. - Wayne at Pelican Parts  
calvin Comments: i have a 1993 bmw 318i and was running fine when i drove to the store and then when i arrived i couldnt roll down the window unless the door was open and then after i turned the car off it wouldnt turn over at all i tried a new battery and still nothing different all the accessories work now windows stereo any ideas what is wrong
September 5, 2010
  Followup from the Pelican Staff: Sounds like some odd electrical problems. I would start checking for wire harness problems, like the one in Figure 2 of this article: http://www.pelicanparts.com/bmw/techarticles/101-Projects-82-Electrical-Problems/101-Projects-82-Electrical-Problems.htm - Wayne at Pelican Parts  
B3M2W8i Comments: I just replaced the serpentine belt and the battery in my 97 E36 and now the car won't start. Any guidance?
August 18, 2010
  Followup from the Pelican Staff: If the car is not turning over at all, then I would check the connections to the battery to make sure they are tight. Also, check to make sure the battery itself is good and charged. If the car is turning over, then you probably need to check the error codes generated by the DME. - Wayne at Pelican Parts  
daxus99 Comments: Hello my 95 BMW 318IC started giving me power problems yesterday. Radio was shutting on and off and I started loosing power in acceleration along with a check engine warning light and other errors in which case my car completely turned off. It started up with a jump start and then died again after 5 minutes. Alternator problem?
August 5, 2010
  Followup from the Pelican Staff: It could be either the battery or the alternator. I would probably start with the easier one of the two (the battery) - remove it and have it checked out at a shop, or if it's old, then simply replace it. Then, if the car still keeps having problems, then I would look at testing or replacing the alternator. - Wayne at Pelican Parts  
the alvn Comments: I've recently had my 1995 325is shut off on me while driving. I recharged my battery to 12.46 volts, tested my charging system and it stayed at 12 volts. Now, I know the reason for this is due to the faulty alternator. My problem is that this vehicle could be equipped with an 80 amp or 140 amp alternator. What's the benefits of the 140 over 80 amps? How do I know which one is the stock item?
August 3, 2010
  Followup from the Pelican Staff: The 140 unit can be used to power more "stuff" like a big stereo unit. Most likely you have an 80-amp unit in your car, although if you install a higher amp unit, it should only draw what amperage the car needs. Although I have heard of people trying to install the higher amp unit and having electrical gremlins after that. - Wayne at Pelican Parts  
tedrien Comments: Where can I find out, or can you show in pictures/tell me how to replace the alternator belt on my 1993 318i?
July 20, 2010
  Followup from the Pelican Staff: Here you go: http://www.pelicanparts.com/bmw/techarticles/E36-Belt-Replacement/E36-Belt-Replacement.htm - Wayne at Pelican Parts  
Dee Comments: While driving car started to cut out then jump forward and eventually cut out altogether. Still turning over for few mins before completely dying. jumped the battery and car started ok but dying again day after. I will fully charge battery for now but think more permanent problem. Any ideas welcome please ? 318Ci 2.0l 2001
June 24, 2010
  Followup from the Pelican Staff: Yes, that sounds like it might be an alternator problem. Test the charging voltage to see what the alternator is putting out, should be 13-15 volts when charging. - Wayne at Pelican Parts  
1994318is Comments: My 1994 318is produced in 11/1993 reads a voltage of 15.5 to 16. So I understand from previous responses that the voltage regulator is bad. My two questions are:
1. Knowing that this is the original 16 years old alternator, am I better off replacing the whole alternator since it is doomed to fail eventually or should I just replace the voltage regulator?
2. Can I still drive the car mostly highway high rev while the order is being shipped or will this cause serious damage i.e. fry the DME/ECU etc..? Thanks.
June 20, 2010
  Followup from the Pelican Staff: That reading is a little high, but not super high. It does sounds like the voltage regulator is going out though. I doubt it will damage your DME or other components, but it might cause overcharging of your battery, which can then lead to acid spilling out. I would swap out the regulator. - Wayne at Pelican Parts  
Werkshop Comments: My lights have this pulsating thing going on. I put in a fresh Bosch Alt in not to long ago. Belts were changed too. I checked looseness in my relays, and cannot seem to find out what is going on. Car starts fine, but the intermittent pulsating of cluster, and low beams are annoying.
April 28, 2010
  Followup from the Pelican Staff: I would check the grounds. Check the ground from the alternator to the chassis. Measure the resistance from the negative battery terminal to the alternator housing - there should be very low resistance there. Also check the grounds on the back of your gauges. Take the housing of the gauge and test it to the battery negative - it should be low - the same as the alternator. If not, then that is probably your problem. - Wayne at Pelican Parts  
diy4life Comments: Wayne I bought your book and its awesome, anyone who owns an e30 or e36 should have one. Now for my problem. I purchased a new battery 9 months ago, its now dead. I checked the voltage when the car is running, its only 11.5 or so volts its around 9.5 volts when the car is off. How do I determine if its the voltage regulator or the alternator itself.
April 25, 2010
  Followup from the Pelican Staff: The E36 alternator has the voltage regulator built in. If the regulator is bad, then the voltage is usually high. If the voltage is low, then it might be the alternator itself. - Wayne at Pelican Parts  
ccazenav Comments: Hi, In my BMW M5 e34 It´s necessary to take the alternator out of the car if I want to replace only the voltage regulator? Thanks.
March 25, 2010
  Followup from the Pelican Staff: I would suggest doing so, although I don't think it is necessary. With it removed, you can inspect it and be sure to properly install the regulator. - Nick at Pelican Parts  
ken Comments: I drive a BMW 318I - 2003 MODEL - lately while driving the engine cuts off and a red light appears for a few seconds then it goes again - couple of time it also stalled and I had to stop for a few minutes but it get going again after switiching the car off about 5-7minutes.It has any original battery. I did tighten the terminals but it still playing up.
What should I do next.
January 28, 2010
  Followup from the Pelican Staff: This sounds like a bad alternator. Monitor charging system voltage while loading the circuit. Load it by turning on your blower motor and headlights. If voltage doesn't hold, the alternator is faulty. i would replace it. - Nick at Pelican Parts  
al Comments: Battery not recharging, replaced battery and voltage regulator, but the charge is still intermittent
January 16, 2010
  Followup from the Pelican Staff: You could have a bad alternator. Even with a new voltage regulator, there could be an issue with the stator or internal wiring. Also check the engine ground and battery feeds. A voltage drop test would be best. - Nick at Pelican Parts  
Al Comments: battery on 2004 BMW M3 starts recharging only after 10 minutes ride.
Replaced the battery and the voltage regulator - the problem still exist.
What else can I check? Thank you
January 16, 2010
  Followup from the Pelican Staff: You could have a bad alternator. Even with a new voltage regulator, there could be an issue with the stator or internal wiring. Also check the engine ground and battery feeds. A voltage drop test would be best.- Nick at Pelican Parts  
31isam Comments: can u replace a 80 amp alternator with a 105 amp unit or will this be too much for the electrical system? i have a 1995 318i m42 and i am replacing the bad 80 amp unit as we speak.
December 16, 2009
  Followup from the Pelican Staff: It's quite common to replace lower amp alternators with higher ones when you're installing aftermarket stereo equipment, etc. However, unless you have any new electrical loads on the system, I would stick with the stock alternator. In theory, the car's bus should only draw as much power as it needs, but with these modern cars anytime you change something like this, there are often side effects. - Wayne at Pelican Parts  
Andrew Comments: i'm trying to replace the mount bushings, but there is a metal tube with lips at both ends, won't come out....how do i replace the bushings?
October 17, 2009
  Followup from the Pelican Staff: Hi there. As far as I know, these are not replaceable. They are also a non-moving part so it's unlikely they would wear out, unless the alternator was not tensioned properly through it's life. - Wayne at Pelican Parts  
325i/1993 Comments: Where can I find the engine ground strap for my 1993 325i?
October 8, 2009
  Followup from the Pelican Staff: It's attached to the right side engine mount on your car. I have a photo of this on page 229 of my 101 Projects Book. - Wayne at Pelican Parts  
Bridgette Comments: What about the 7 Series - is it the same procedure?
September 18, 2009
  Followup from the Pelican Staff: Yes, it should be very similar to the one detailed here. - Wayne at Pelican Parts  
Stixx Comments: Can bearings be replaced also ?
May 20, 2009
  Followup from the Pelican Staff: Yes they can be replaced, but an alternator shop usually needs to do this as there are no "bearing repair kits" that I am aware of. - Wayne at Pelican Parts  

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