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  1. #1

    Default A/C low presusre switch replacement advise.

    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?
    Thanks.
    2011 Chevy Silverado LT 4WD 25k miles
    2001 Suburban 2WD, 5.3, V8 176k miles
    1993 964
    1996 318TI

  2. #2

    Default

    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.
    2011 Chevy Silverado LT 4WD 25k miles
    2001 Suburban 2WD, 5.3, V8 176k miles
    1993 964
    1996 318TI

  3. #3

    Default

    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...
    Joseph


    Airforce Veteran (7 years)


    NRA Life Member

  4. #4

    Default

    Quote Originally Posted by Joeairforce View Post
    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...
    Thank you for the tip. That's great to know. I have not done it yet. Planning to do it this weekend.
    2011 Chevy Silverado LT 4WD 25k miles
    2001 Suburban 2WD, 5.3, V8 176k miles
    1993 964
    1996 318TI

  5. #5

    Default

    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.
    Click image for larger version. 

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    Click image for larger version. 

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    2011 Chevy Silverado LT 4WD 25k miles
    2001 Suburban 2WD, 5.3, V8 176k miles
    1993 964
    1996 318TI

  6. #6

    Default

    Oh I did not replace the switch, I just replace the o-ring.
    2011 Chevy Silverado LT 4WD 25k miles
    2001 Suburban 2WD, 5.3, V8 176k miles
    1993 964
    1996 318TI

  7. #7

    Default

    Quote Originally Posted by bazar01 View Post
    Oh I did not replace the switch, I just replace the o-ring.
    Probably saved $600 by not having the stealership do it.

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