94 325is gauges acting crazy
 

When I start my car the gauges go crazy. The instrument cluster clicks on and off and the needles jump all over. I took out the cluster and the wires look ok in the back. Taking apart the cluster didn't give me any clues either. Any help would be greatly appreciated.
http://i808.photobucket.com/albums/z...r707/photo.jpg

Not sure right when they changed the SI boards but that cluster may have a slide out board in the bottom of it with a couple of rechargeable batteries soldiered on to it. The batteries go bad, the board needs to be replaced/rebuilt. Be careful cut the old ones off, soldier new ones on and hopefully that solves it. just taking a stab since mine did that too in an e30 with the same cluster.

Thanks for the reply. :) There were no batteries when I took the unit apart from what I remember. I have found one on ebay for about $100.00 and I think I am going to bite. I am hoping that the issue is with the cluster itself and not something else. It doesn't seem to be a short because the guages have no activity for about 15 seconds and then they go bonkers. Also the "clicking" sounds like it is coming from the instrument cluster itself. I am guessing there is a bad capacitor on the board inside the cluster.

That too could be a distinct possibility. If your's does have the board I'm thinking of it's rather hidden and 90 degrees to the main board on the back slipped in under the gauge faces (the service led's are on it). I know there was a production change near the e30 to e36 change over to eliminate them because they were such a pain so you may not have them. But good luck, hopefully it all works out.

Hmmm... Going to check the thing again haven't put the screws back in yet....

No batteries here. Gonna order the replacement I guess... Will let you know how it goes......

Well the replacement finally arrived today and it did fix the problem. All gauges work like a charm. :rock One thing I did notice is that the odometer reads the miles from the cluster I installed. It doesn't seem to be taking the mileage from the computer. I thought it would take the higher of the two and I am sure the car has more miles than the cluster. Any ideas out there of why it isn't updating the miles. Thanks.

you need the coding plug to tranfer the milage from one cluster to the other.

Thanks for the reply. It seems the other cluster is shot, does that mean I am out of luck? Not to big of a deal as I dont plan on selling the car anytime soon, but I would like to get the proper mileage registered on the car.

i believe the coding plug simply stores the info like a ROM but i may be wrong though.

I think Scooter is right, its the plastic plug with the long post on it that has a number on the end, swap it over, see if it works. Congrats on the working gauges though.

Thanks a lot for the responses. Turns out that a 94 instrument cluster has no coding plug and that it is on a eprom chip on the board. I am not going to go through the trouble of removing a sodered on chip. The funny thing is that the red light that should come on is not. Oh well.

is the milage on the new cluster higher then your old one? if it is its probably the reason why the tamper light isn't coming on, another could be the the lack of coding plug.

Nah, the mileage on the cluster is about 227k and the last carfax reported mileage in 07 was over 235k. The old cluster was messed up and didnt show the mileage. You can see how screwed up it was by the picture in the 1st post. Thanks again for the response. :cheers

Evidently , just the unplugging and replugging of the clusters from - and to - the display guages , can sometimes work to ' refresh ' the contacts , and this can address the problem . The contacts become a bit oxidised with time and this breakdown in communication between pins and clusters results in display going berserk , and switching in and out at random .