Bill,

Just two quick thoughts I'm not an expert on your particular system but I'm pretty sure you have a circuit that compares the compressor speed with the tach signal and the compressor slows down the circuit disengages it so you don't fry the belt. Check for proper belt tension and condition. Also I think but am not sure, that by 85 MB had added the grimlin infested KLIMA relay to the system. If so it resides inboard from the fuse box just aft of the compartment bulkhead. Pull it out and check for burned contacts where it plugs in.

Bob D.