larry,i've seen speed sensors go bad and i've seen compressor shafts worn so that they are too far away from the s/s to create enough voltage to hold in the klima relay.then there is the possibility that the klima relay is at fault.i suggest that you jump the klima relay from term 15 to term 87[next to each other] and run car to see if compressor clutch is faulty.[could be a tiny break in magnet wiring that is dropping clutch] this provides the safety on shutting power down to clutch with key off.if this test successful then we can move forward to isolate the problem. david poole european performance dallas tx.