PeachParts Mercedes-Benz Forum - rpm sensor on the AC compressor

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My car is an 87 Euro 300D. I'd like to know why MB put an rpm sensor on the AC compressor. What is it's function? Where does the AC rpm signal go to?

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Jake

MB put an rpm sensor on the compressor to keep a slipping or locked compressor from overheating or breaking the drive belt. One belt driving many things...if the belt breaks, you have no water pump, alternator or power steering. The rpm signal from the compressor goes to the Klima relay and is compared to an engine rpm signal. If the difference between them is too great,the compressor clutch disengages.Really a simple system when you think about it.

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W.R.Durrance
ASE Master Tech
Mercedes Tech 19 Years