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A/C superheat switch - where exactly is it? V70-XC70 1999

This is a link to a photgraph of my compressor:
http://www.the-cohens.org/volvoac.jpg

(I don't know if this will appear as a clickable link. You may have to copy and paste it into a browser window.)

I was thinking that the black block only held a diode, and that the wire went into the compressor body somewhere out of sight, but at closer inspection, it really looks like the wire goes directly to the compressor clutch once it goes out of sight. Is the superheat switch actually inside the black block?

What function does the diode serve at that point in the circuit?








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    A/C superheat switch - where exactly is it? V70-XC70 1999

    Peter,
    The black block is a diode. It's there to short out the back EMF that is created when the clutch is switched off. It protects the relay contacts, prevents them from pitting.
    I measured the voltage on the clutch side of the diode and had voltage there while the clutch was not engaged. Can't figure that one out.
    --
    Tom 69-1800S, 72-1800ES, 96-850T








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      A/C superheat switch - where exactly is it? V70-XC70 1999

      This was posted on www.aircondition.com in response to my question about what the black block is:
      " Its a temperature sensor in series with the clutch coil. If the case gets too hot it opens and shuts down the compressor. Honda has a similar round one held in depression on the top of the compressor. I've had two of these go bananas and start to open way too soon. You can jumper across it if you thinks its causing trouble."

      I guess the next time things get hot, I'll see if there is voltage on both sides of it. If not, I'll go buy a diode and make a jumper wire.







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