Instrument Cluster fail

[M42_Jester]

ok...so my Tachometer has been virtually non-existent for a while now, and i finally decided to do something about it. I bought a second hand Instrument cluster and swapped the two over. Only problem is, the instrument cluster i bought is not from the same model car as mine and made a horrible beeping sound when I connected it.

Opening it up, I could plainly see that the 2 circuit boards are very different. So I connected the dials from the second hand cluster on my old circuit board, connected everything up and started the engine. Tachometer still didn't work, but fuel and temperature gauge did. Took her for a drive, and noticed that the Speedo was no bust. Took it all apart again, and replaced the second hand speedo with my old one, and tried again. Speedo now works.

Now, because my Tach was broken, before I bought the second hand cluster, I decided to see if I couldn't fix the motor myself. When I looked at it, the copper wire that drives the motor was all twisted and bent. Upon trying to straighten it all out, it broke. So my old Tach motor is basically just the motor with 2 plastic gears and nothing to make it move.

Finally, here is my question. If I was to take the gear out of the bought clusters Tach motor, and replace my broken one with that, will it work?
My fear is it will not, as there may be a problem with the Circuit Board itself, but is it worth the trouble trying to fix it this way?

Any help will be very much appreciated.

Cheers,
Jester

[DesktopDave]

IDK about the e36 clusters.  There are two types (VDO & Multimeter) for the e30, I wonder if BMW switched suppliers mid-stream on e36 production too?

I'd take a good look at the driver board of each cluster to see if there are any bulging or leaking capacitors.  Soldering is a rewarding hobby.  Other components are more difficult to troubleshoot.  Did you swap the coding chip plug?  Try this too:
http://www.unixnerd.demon.co.uk/e36trick.html

[M42_Jester]

cheers for the quick reply DesktopDave

I'm pretty sure my cluster is a MotoMeter...says it almost everywhere on the thing just by remembering what the circuit board looked like, i don't recall any leaking anything...and i tried that little test you mentioned. very interesting. all the needles moved like they were supposed to...so now i'm thinking there is a bigger problem...wat components drive the Tach?

Jester

[DesktopDave]

I'd guess tach drive is from the crank sensor, but if it's filtered by the DME I'm not sure which pin it might be.  Maybe a wiring problem in the cluster connectors or the cabin/dash grounds on the firewall?

Early e36's have a tendency to flood their DMEs in car washes or heavy rain, that might have something to do with it too.  Not sure what year you have...if so, have you done any surgery to correct that?

[M42_Jester]

I have a 95 318iS...truly a one of a kind xD

but i hav been told by my mechanic that the DME did get wet and needs repairing...it's also knocked out my alternator cut off switch or something...wateva it's called, when my A/C is running, it won't turn off when the car does... i was simply hoping that i wouldn't hav to fork out close to $1K to fix it...but looks like i may have to *sigh*

on a lighter note...i took video of that cluster test check it out

http://www.youtube.com/watch?v=nQNP37tzfqo

Jester