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Pelican Technical Article:

Voltage Regulator Replacement

Steve Vernon

Time:

1 hour1 hr

Tab:

$40

Talent:

**

Tools:

7mm wrench, flathead screwdriver, paper clip

Applicable Models:

VW GTI (2006-09)

Parts Required:

New Voltage Regulator

Hot Tip:

ALWAYS disconnect the battery before beginning

Performance Gain:

Car charges again

Complementary Modification:

Change drive belt

The alternator charges the battery and provides your car with a constant source of electricity while the engine is running. The voltage regulator does just what it says: it regulates the voltage from the alternator. Your battery should read a little more than 12 volts with the engine off. Next check the voltage of your charging system under load, the voltage should be within 13.2: 14.5 volts d/c. To load, have engine running at idle, turn on headlights and HVAC blower motor. Never disconnect a battery cable while engine is running to test alternator, you may cause damage to alternator or other electrical components from the surge in amperage. If your battery appears to be leaking, then 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 14.5 volts when the engine is running, then the voltage regulator is probably bad. If your battery has boiled over and has acid overflowing out the top, make sure that you clean up any spilled acid 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.

A large amount of the time when there is an electrical problem with the charging system it is the voltage regulator, yet people just swap out the entire alternator because it comes with a new voltage regulator included because it is easier, fixes the problem and most people do not understand how an electrical system works on their car. If your electrical issues are caused by a faulty voltage regulator you can save your self a lot of money by just replacing the defective part.

You will have to take the alternator out of the car to replace the voltage regulator. Please see our article on replacing your alternator. You must perform this work first.

With the alternator out of the car take it to your work bench and turn it over.
Figure 1

With the alternator out of the car take it to your work bench and turn it over. There is a plastic cover over the back that is held in place by three friction clips on the studs (red arrows) Use a screwdriver and gently pry the cover off.

With the cover off you can see the voltage regulator (red arrow).
Figure 2

With the cover off you can see the voltage regulator (red arrow).

Use a 7mm wrench and remove the three bolts (red arrows) holding the voltage regulator in place.
Figure 3

Use a 7mm wrench and remove the three bolts (red arrows) holding the voltage regulator in place.

With the regulator off you can see the two
Figure 4

With the regulator off you can see the two "brushes" (red arrow) that make contact with the poles on the alternator. These are held in place against the polls by springs that can wear out; the brushes can also wear out or become excessively corroded over time.

While the regulator is out make sure you check the condition of the poles (red arrows) on the alternator: they can be discolored but should not be excessively worn, corroded and should not have grooves worn in them.
Figure 5

While the regulator is out make sure you check the condition of the poles (red arrows) on the alternator: they can be discolored but should not be excessively worn, corroded and should not have grooves worn in them.

Installation is the reverse of removal.
Figure 6

Installation is the reverse of removal. You will need a small paper clip to compress the brushes when installing the regulator onto the polls. Once the regulator is in place simply wiggle and pull the paper clip out.

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Comments and Suggestions:
Adrianna Comments: I have a 1983 rabbit GTI. The volt meter is topping out immediately upon starting up the vehicle 16 volts +. Some of the other gauges are a little touchy, for example the rpm meter and thermometer sometimes work and sometimes the needle goes all the way to the right. I am guessing there are some electrical issues going on, but am worried about the high volts. How can I tell if it's the voltage regulator or just an issue with the gauge?
June 15, 2017
  Followup from the Pelican Staff: Check charging system voltage and current using an alternator tester. - Nick at Pelican Parts  

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Page last updated: Thu 11/23/2017 02:36:28 AM