BMW Repair: Instument Cluster, bad rain, rain storm

Question
John,
I have a 93 325i with an automatic transmission.  It has about 190k on the car and 130k on the motor.  My problem is that the instrument cluster does not register anything.  You can faintly see the odometer but it does not appear to adding miles.  Sometimes the buzzer that tells you that yours keys are in the ignition will ring the whole time I am driving.  Also the OBC will not compute any data.  Nothing driving wise is effected.  I have checked fuses and there is nothing blown.  This problem seemed to have started during a bad rain storm and I have heard the DME can get damaged but typically this will effect the way it drives. If you can help me with this I would be greatly appreciative.

Answer
First, double-check fuses 23, 45, 3, and 47.  These all impact the OBC.  27 and 31 are for the instrument panel.

Beyond that, there is a massive amount of wiring and grounds that could impact this, too much for me to try to debug remotely.

Also, check if the OBC is actually not working, or just not lighting.

Good luck!