A/C low presusre switch replacement advise.

Discussion in 'Chevy Suburban Forum (GMC Yukon XL)' started by bazar01, Jul 10, 2012.

  1. bazar01

    bazar01 Rockstar 100 Posts

    My A/C started leaking refrigerant at the base of the pressure switch located at the drier/liquid accumulator. I noticed it when the A/C stopped cooling due to ice blockage on both the front and rear evaporators. There was oil around the base connection.
    Any advise on replacing this switch without pulling all the R134A from the system? I was thinking of releasing some of the R134A by depressing the schrader valve to lower the system pressure and just unscrew the leaky switch and install the new one. This way, no air will enter the system. Then just recharge the system using a recharge kit from the auto parts store. Any comments?
  2. bazar01

    bazar01 Rockstar 100 Posts

    I called the dealer today and learned there is an o-ring at the switch. The dealer calls it the a/c cycling switch and not a low pressure switch. Well to me it basically is the same since it senses the low pressure side of the system to cycle the compressor off and on based on the low side pressure.
    O-ring PN 3093509
    Cycling switch is $46

    I will try to tighten it first and see if that fixes the leak. Then replace the switch next.
  3. Joeairforce

    Joeairforce Epic Member 5+ Years 100 Posts

    You don't need to drain anything to replace it... Just unscrew it and screw the new one on.... It sits on a schrader valve itself so you won't lose anything during replacement...
  4. bazar01

    bazar01 Rockstar 100 Posts

    Thank you for the tip. That's great to know. I have not done it yet. Planning to do it this weekend.
  5. bazar01

    bazar01 Rockstar 100 Posts

    Just got this done today. A big thank you to Joe. The switch just unscrew out without losing refrigerant. It is mounted on a schraeder valve. I also went ahead and recharge one more can of R134A. It is cooling way better than before.

    Here is with the switch out.
    switch out.jpg

  6. bazar01

    bazar01 Rockstar 100 Posts

    Oh I did not replace the switch, I just replace the o-ring.
  7. Ozlander

    Ozlander New Member

    Probably saved $600 by not having the stealership do it.

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