W210 Instrument Cluster Not Working
 

I have a 96 E320 and the instrument cluster gauges have stopped working. Recently, I had the AC compressor replaced and I thought that maybe something had been disturbed because the gauges worked for the 16 years that I've owned the car and stopped after the AC work. The intermittently come on and off, but lately they don't come on at all. The display in the center that shows mileage, temp etc still works, along with the low fuel light, but the gauges don't move at all. I have an extra instrument cluster out of a junk car which worked in the past, so I put it in and it doesn't work as well, so it may not be the cluster itself. Is there a connection in the engine compartment that I should check? The mechanic that changed the AC compressor mentioned something about a "SAM" unit; does this make any sense? Any help would be appreciated.

Were you ever able to solve the problem with your gauges not working? I have the same problem with my 1997 E420. None of the gauges work although the mileage continues to register. The gauges to work occasionally however after turning the car off they will not work again for some time. I want to narrow down the problem before I start investing any money as a trial and error for the repair.