A/C compressor won’t start

Discussion in 'KK General Discussion' started by Doug1125, Jul 10, 2020.

  1. Doug1125

    Doug1125 New Member

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    Hello, 2002 Kk, ac compressor won’t engage. I verified low pressure switch is not cause. Also checked fuse and relay. There is no voltage to compressor, so I’m thinking high pressure switch, but I need help troubleshooting that. Thanks in advance.
     
  2. DadOSix

    DadOSix Full Access Member

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    The high side switch should function as normally closed, until high side pressure is excessive. Then it opens to prevent more damage.

    best to hook up gauge set and verify pressures.

    if pressures are equal, and about outside temp reading Ie - 85 f outside, the ac at stasis should be 85ish, both sides. At that point, you could safely jump the high switch BREIFLY to see if the compressor engages.

    if not, gotta look elsewhere.

    do you have a vom / multimeter that reads ohms? Check the clutch coil resistance.

    i know you said there is no power to the clutch. Does the 02 have a snowflake button?
     
  3. Billwill

    Billwill Full Access Member

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    Is this a 2002 KJ or 2012 KK?

    Either way you need to measure if the AC clutch is getting +12 volts across itself. One side goes to ground while the other side picks up +12 volts from the AC Relay. You should hear a loud "click" when the clutch engage. The ground point may be bad!

    Then do as DadOSix suggested and with the clutch coil disconnected check if the coil is open circuit.

    The clutch may be activated but slips so a new clutch friction plate may need to be fitted with the correct amount of shims installed.

    Do not run the AC with the clutch jumpered out as you will damage the compressor if it is low on refrigerant!:eek:
     
  4. Doug1125

    Doug1125 New Member

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    Hi, thanks is for all the info. There is no voltage to the compressor. I checked the fuses and relay and they are good. It’s a 2002. The pressure gauge on the low side is in the red. I’m assuming it’s out of refrigeratnt, since there appears to be a leaking hose.
     
  5. sota

    sota Full Access Member

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    well, there you go.
    you can always jump the relay and kick the compressor over to test that it still spins, but if you're out of fluid don't do it for too long.