Did your tach
suddenly stop working? Have all your gauges suddenly gone dead for no
reason? Are the service indicator lights dead? Chances are that the
batteries on the service indicator board have gone dead. This is pretty
common problem on the E30 BMW models. In this tech article we will discuss
replacing the batteries and get that service indicator working again.
E30 3 Series as well as other BMW models have a neat little feature that
illuminates a row of lights over a certain amount of miles and informs you
of when routine service needs to be performed on these cars. Normally,
simply running the car re-charges the batteries and keeps the service
indicator lights operating. Sometimes, however, the batteries can fail,
causing the lights to go dead. It can also cause the tachometer and other
gauges to stop working as well. In the case of my car, the lights stopped
working as well as my coolant temperature gauge. The tachometer also started
jumping erratically and then finally stopped moving.
the batteries are located in the instrument cluster, it is necessary to
remove the cluster. The first step is to remove the steering wheel. Use a
flat-head screwdriver to pry out the steering wheel emblem, underneath; you
will see a 19mm nut holding the wheel to the steering column. Make a scribe
mark or paint mark to align the steering wheel in the right position when
you re-install it. Now, remove this nut. Next, rotate the key to the on
position, but do not start the car. Turning the key will disengage the
steering wheel lock and allow you to remove the wheel. Now pull the steering
next step is to remove the lower panel under the dash, remove the three
plastic screws in the front of the panel and the other three screws holding
the panel on at the bottom. Now remove the panel. Next, we will need to
remove the lower dashboard fascia panel in order to provide clearance to
remove the instrument cluster. Reach up under the dash on either side of the
fascia piece and feel for a knurled round nut on either end. Loosen and
remove these nuts. You can now remove the fascia piece.
look at the bottom of the instrument cluster; you will see four screws
holding the mounting frame to the cluster. Remove these. Next look at the
top of the cluster. You will see two screws holding the frame into the dash.
Remove these as well, and pull the mounting frame free of the car. Use
caution as you do this. The frame is very fragile and can break off the
upper mounting flanges very easily.
with the frame off, you can now remove the instrument cluster. This may take
a little time, as you will have to rotate the cluster around so you can
disconnect the various electrical connections in the rear. Take a look at
the back and mark each connection. Now disconnect them all. You should be
able to remove the cluster from the dash now.
the cluster out, take a look at the backside. I should take this time to
point out that not all gauge clusters look the same, BMW had a few different
manufacturers for the clusters, but for the most part they look the same.
You should see some Phillips head screws around the perimeter of the
cluster. Remove all these, and you should be able to lift the backside of
the cluster off.
at the center of the cluster. You will see a single Phillips head screw
holding this plate on. You must remove this screw to access the S.I. board.
Now remove the plate, and grabbing the board by each side, pull it directly
out, using care not to break or damage the board.
with the board out, look for the two Ni-Cad batteries, they wont be hard to
miss. This is what we are replacing. Be sure to get a hold of two NiCad
AA batteries that are 3-volts (not the regular ones you find in the store,
they might have to be found at a specialty retailer like Radio Shack). You should be able to pick these up at Radio Shack or
Freys Electronics. Note the service indicator LEDs on top. Simply pull up
on the light board and it will pull off.
get your soldering iron out and let it warm up. You will want to use a
low-wattage soldering iron to remove the batteries; otherwise you risk
frying the board. 10-15 watts should be the max. Also, familiarize yourself
with the battery polarity and make sure you understand which way to solder
these batteries into the board. Once the soldering iron is ready, unsolder
the old batteries. They should pop right out of the connectors when the
solder is removed. Before you install the new batteries, make sure they have
had time to charge. Now, making sure that the polarity is correct, place the
batteries in the connector, and then solder the connections. Keep in mind
that we re working around sensitive electrical components, so its a good
idea to use an anti-static wrist strap.
the new batteries in place, now is a good time to test the various light
bulbs in the cluster and replace any burned out bulbs as needed. I found a
couple that needed replacement. Place the LED board back onto the S.I.
board. Now, place the board back into the cluster and slowly push it into
place, making sure that the pins line up correctly at the bottom. Re-install
the access cover and the single Phillips head screw holding it in place.
re-install the rear cover of the cluster and tighten the Phillips head
screws. This done, we are now ready to re-install the cluster back into the
dash. Reconnect the electrical connections on the back of the cluster, and
rotate the cluster so it is oriented facing towards you.
re-install the plastic frame around the instrument cluster and screw it down
in place. Once tight, install the two screws through the mounting flanges
and up into the dash. Take care when doing this that the cluster is properly
aligned. If not, loosen the screws, re-align, and re-tighten.
reinstall the lower dash fascia plate and reaching from under the dash,
install the two knurled round knobs. This will pull the fascia plate tight
against the cluster.
re-install the lower dash panel and tighten the three plastic screws in the
front and the three screws in the bottom. With the lower dash panel on, use
the scribe or paint mark from earlier and re-install the steering wheel.
Once in place and when it is correctly oriented, put the 19mm nut back on
and torque it to 50 ft/lbs. Place the steering wheel emblem back in place
making sure it is lined up correctly.
Well, there you have it - it's
really not too difficult at all. If you would like
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