Originally Posted by Strife

I also can remove a wheel, airbag or not, and cluster in 15 minutes at this point. About grounding, etc, the soldering mentioned should conclusively end this problem.

While I was working on my 380SL, I found another interesting problem; the round 12-pin connector is keyed. However, the key can, and does, break off (and I was careful), allowing this connector to go in offset. This can lead to very strange problems or possible damage to the leftmost gauges upon reassembly. If the plastic tab in the middle of this connector is broken off, be VERY careful in realigning the connector - align by the missing pin and associated wire on the connector. The flat part at the top is NOT correct in that it is NOT parallel to the instrument cluster, so you can't use that as a guide.