1989 525i Instrument Cluster Problems AGAIN!

[cew1989]

I changed the instrument cluster capacitors (all 5) and my battery still drains overnight. The gas mileage gauge moves spastically approximately every 60 seconds, etc. Any ideas.

[shogun]

Your battery drain has nothing to do with the capacitors.
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If you are a beginner in electric issues, this walks you through it, hopefully:

I'll try to make it simple, ...

The meter should have an A scale (Ampere) for reading current. Preferably, a High amp one (10A for example). In some of them, this high amp scale requires the red plug of the wire probes to be connected in a different hole. We do not know the magnitude of the current involved, so in order to preserve the meter, it is better to start reading in this high amp scale.

Disconnect the ground (negative) lead to the battery (electronic devices in the car will loose status when battery is unplugged, so you will need radio code for example), connect the positive (Red) meter probe to the negative thick wire to the battery, and connect the negative (Black) probe of the meter to the negative battery post. Be sure that the probes are inserted in the proper holes in the meter for the readings (Amp) you intend to take.

If you have a leak as you assumed before, you should have a significant reading in the meter (maybe/sometimes more than 50 milli amps, > 0.05 Amp). If the selected scale do not allow you to have a clear reading of the leaking current and you want to change down scales, do so. Remember that some meters require to select a new hole in the meter for the red probe in order to select a lower Amp (Current) scale.

Once your meter is properly set and you have a good steady reading of the leaking current, proceed to remove, one by one, the fuses on the fuse box. Keep an eye to the meter in order to identify which fuse removal is dropping down the current in the meter. The leaky circuit is feed by that fuse.

Investigate what devices are associated to that fuse, plug the fuse back, and start disconnecting all devices one by one until you get again a reading drop. That device would be the culprit.

Written by Javier, and slightly changed by me to fit such question in general.
Hope that helps.

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[cew1989]

Still baffled. Thanks much for your help. I followed your instructions, pulling all fuses and watching the meter, but none caused the meter current to drop. There was definately amp current on the meter (it registered off the 12 amp gauge). I also noticed that, with the engine off and the key removed, the instrument cluster lights repeatedly came on and "glowed" for approximately 15 seconds and often flashing, the fuel consumption gauge spastically moved, etc. Any additional ideas?

I appreciate your help. This problem has me extremely baffled.

[shogun]

What about the ground cables? As I said on PM, I had a similar prob 6 months ago, all went berserk in the cockpit, even the blower fan did not stop. Finannly turned out that 2 cables were lose in engine room in main engine harness. Long time required to check all wires.

[cew1989]

What do you mean when you say the ground cables? Can you tell me how to check them?

Thanks much