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850 AC compressor on intermittantly

posted by  dandonnell on  Mon Jun 26 12:08 CST 2017
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OK, my daughters 96 850 wagon AC compressor comes on sometimes. Assuming enough freon to trigger the low pressure switch what other electrical problems could cut power to the compressor? The other day after the car had been sitting for over a week the compressor came on which surprised me since I know it has a slight leak. This means it at least had enough freon to make the low pressure switch. I suspect freon was a little low as it would only cool to around 55F at idle but the compressor was not cycling off & on. Havent checked with gage yet but have in the past and after adding freon it would stop cooling when driving aqccording to her.

It seems to point to an electrical problem cutting power to the compressor. Sometimes when she drives it does cool and the compressor doesnt come on.

Any common issues i need to investigate? Relays, climate control air inlet fans over grip handles, dash on/off switch?
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It takes a great deal of intelligence to recognize ones own ignorance








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    850 AC compressor on intermittantly

    posted by  KlausC on  Mon Jun 26 15:44 CST 2017
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    last visit: Fri Oct 24 10:15 CST 2014
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    It takes a minimum 12V to engage the clutch. The hotter it is, the more voltage it takes. Plus, when the clutch plate wears, it takes more juice to pull the clutch all of the way to the electromagnet.

    I would check the clutch gap, it needs to be around .025 for optimal range. Usually at around .040, operation can become iffy.

    If the compressor gets too hot, there is a thermal cutoff. Usually caused by a low charge.

    IF you over charge the system, the evaporator can build up ice. Blowing 'cold' at 55F sounds nice to me.
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      850 AC compressor on intermittantly

      posted by  dandonnell on  Mon Jun 26 20:32 CST 2017
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      Hi Klaus and thanks for the Response. I guess its possible it could be the compressor gap but what makes me think it's not is that the cooling fan should start up when the compressor starts. If it was the clutch would not the cooling fan still come on and the clutch not fully engage enough to spin the compressor? So far, whenever the compressor is not engaged the cooling fan is off and when compressor is on fan is on.

      I have noticed a few times the off/on switch on the dash doesn't always respond with the orange light the way I would expect, sometimes the light goes off and on with a delay after pressing switch.
      --
      It takes a great deal of intelligence to recognize ones own ignorance







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