Well tonight I just got tired of trying to see what speed I was going in the dark. It appears that the last of my dash bulbs finally burnt out....Time to R&R the Instrument cluster. Pulled the cluster, fixing the trip odometer while I was at it...Everything looked good. Put it back in and even though now all my gauges work without pressing on the upper left corner of the IP (instrument panel) I have a new and strange problem. When I put on high beams my tach shows 0 and all the other gauges peg out at their high points....Could I have pulled a ground loose or something when I was trying to get everything unplugged???? May have to pull the cluster in better daylight so I can see everything more clear...Any ideas? Or has anybody seen this before?? Are the bulbs for the seat belts and glow plugs hard to find?? They look like real small bulbs. I was lucky in that the one in my shift lever was just loose...

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Looking for another Mercedes 300D or SD as a project vehicle..

The instrument panel is missing the ground, best way to fix it is to run a new ground wire to it.

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Which screw on the back of the panel can you attach a wire to to make a ground?? Or does it have to be soldered onto the circuit board somewhere??? I kinda figured I might have broken a ground wire, but wasn't sure...I know you have about 9 screws on all 3 parts of the instrument cluster, wasn't sure which one connected to the ground circuit of the IC....

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Looking for another Mercedes 300D or SD as a project vehicle..

The instruments are three seperate modules, gauges, spedo, tach. The speedo has a metal strap that provides ground all the way across, so all the screws have to be tight, but not so tight that you crack the plactic..........