BMW Repair: Tachometer, fuel comsumption, 325 bmw

Question
Have a 1987 325 BMW - Tachometer does not work, nor the associated, fuel comsumption indicator.  How do I start troubleshooting this problme

Answer
mrcm,
 I would first start by removing the cluster from the dash.  Pretty simple to do, maybe 6 screws holding everything in.  Once you have the cluster loose, fold it forward, and make note of every electrical connection (write them down) Unplug all the connectors and slide the cluster out of the right side of the steering wheel.  Open the cluster and check the service indicator card (circuit board that plugs into the front half of the cluster, not the main board).  The SI board will have batteries on it, you can go to radioshack and get new ones.  These need to be soldered onto the board, so if you are uncomfortable doing this, then take it to an electronics repair shop and they should be able to help.

 Check over both boards and make sure there are no black or melted spots, as the WHOLE board will have to be replaced if this is the case.
 
 Hope this helps,
 Josh