intermittent gauge problem.. HELP!!

[my3rdbimmer]

I posted this in the M section too but this area gets more action so i though i'd try here too...

Just got my 95 M3 yesterday... and i love it~!!!!

That being said, I bought it knowing it has been having an intermittant gauge cluster problem.. I also paid 1200 less than what they were asking becasue of it..

symptoms:
-the gauge cluster will cut out..

-all gauges will go to zero..

-the mileage indicator as well as all indicator (brakes check engine etc) lights will go out seemingly for no reason that i can reproduce.

-after a period of time everything will come back on..

-all the lights will flash and the dinger will ding jus like it would if you just turned the ignition on.. the car runs fine through all this....

-The dash illumination lights stay on (when the headlights are on ) like they should..

-it just seems to effect the instrumentation.

the longer i drive the less it happens it seems....


This car was meticulously maintained by the dealership..every oil change and service done... and only had 64,000 miles on it just had its inspection 2 and the dealership replace the ignitionswitch thinking it would correct the problem.. the owner decided to buy a new M5 and did not want to put any more money into the problem.

the only gauge related problem i can see in this thing's history is hat the fuel sending units were changed out in 97.

i am a pretty good mechanic with a little below average electrical and electronic skills so i defer to you experts out there.. is any on else having or have had this problem

thank you in advance for your help..

 

[adrean8j]

I am also not an expert but to me it sounds like an intermittant short in the wiring to the gauge cluster. The wiring to the actually gauge readings is separate than the gauge lighting so thats why the lights stay on....it would take me see a wiring schematic and a multimeter to figure out the rest......but my semi-educated guess would point there(I work in the communications field but there a many "troubleshooting" parallels in electronics)

 

[kerph32]

This may help-

http://www.m3forum.net/m3forum/showthread.php?t=124396

 

[my3rdbimmer]

ok... now i have found out that when this happens the wipers cut out also... is there a comon wire that feeds.. all of the gauges the check lights, the odometer and the wipers..

 

[Kirby]

I have not personally experienced this problem, but here are a few suggestions based on other experience over the years:

- Unlikely, but it could be an intermittent fuse. Once in a great while, a fuse can fail mechanically where the element gets a crack in it and it acts like this. Fuses can also get corroded where it plugs in. It's quick and easy, so check or replace the fuse just to eliminate that as a possibility.

- A plug connector can also cause this, similar to the intermittent fuse above. I would remove and inspect the connectors that attach to the instrument cluster.

- A bad circuit trace in the instrument cluster. Most of the clusters I have worked with use something similar to a "printed circuit board" design where copper strips carry the voltage/signals in the cluster. Due to flexing or abrasion, these traces can break.

All of these things are not common, but cluster failures are fairly uncommon anyhow. As Marc said, this really calls for a schematic diagram (Bentley manual) and a multimeter.

 

[jrt67ss350]

- A plug connector can also cause this, similar to the intermittent fuse above. I would remove and inspect the connectors that attach to the instrument cluster.

- A bad circuit trace in the instrument cluster. Most of the clusters I have worked with use something similar to a "printed circuit board" design where copper strips carry the voltage/signals in the cluster. Due to flexing or abrasion, these traces can break.

All of these things are not common, but cluster failures are fairly uncommon anyhow. As Marc said, this really calls for a schematic diagram (Bentley manual) and a multimeter.

Actually, these last two suggestions are VERY common, at least in the E30. I actually had a similar issue with only some of the cluster indicator lights in my e30, and it turned out that one of the solder joints on the circuit board for one of the cluster plug connectors had a very small crack in it. Resoldered the joint and it completely corrected my issue. I imagine the E36 cluster is probably a similar design.

Not sure how that would relate to the wipers, though.