Air Conditioning ?

Discussion in 'Chevy C/K Truck Forum' started by corvetteman, Jul 13, 2011.

  1. corvetteman

    corvetteman Member

    1992 Suburban 2500, What is the easiest way to check the a/c compressor? When I turn it on I do not hear it engage. Thanks
  2. Chris Miller

    Chris Miller Rockstar 100 Posts

    Remove the connector from the clutch cycling switch on the accumulator(big metal can). Short the connector with a paper clip or whatever and then turn on the A/C. While you're doing that, check your freon charge. It should be around 30-50 PSI. If it's more than that, shut it off! That means you've got something blocking the line. If it's too low, add more freon, and see what happens. If it doesn't leak out, you're good.
  3. 2COR517

    2COR517 Epic Member 5+ Years 1000 Posts

    Start with a pressure gauge.
  4. corvetteman

    corvetteman Member

    So if the compressor turns on when I short the switch that means the switch is bad?
  5. Revredneck

    Revredneck Rockstar 100 Posts

    If it cools well with the pressure switch shorted, then yes, it's a bad switch. They have a schrader valve in the fitting so you can just screw it off and screw a new one right back on it. It try to do it with it running because the pressure is lower and you lose less freon if the valve happens to leak a little bit. By the way, it's called a "pressure cycling switch," so you ask for the correct part if you need one.
    Good Luck and God Bless
  6. corvetteman

    corvetteman Member

    Yippee, the compressor engaged when I shorted the switch with a paper clip. The air is not very cold though.

    Do they still sell Freon for a 1992 at auto store to recharge the system?

    Also where is the Schrader valve I’m unable to locate it? Thanks
  7. starsilverado

    starsilverado Rockstar 100 Posts

    Chances are the pressure switch is doing its job and the refrigerant charge is low. Dont run your A/C with the switch jumped out or you risk ruining the compressor.YThere should be a label near the emissions label telling what type and the amount of refrigerant you need. your auto parts store should have what you need to recharge your A/C. Good luck!
    Also the schrader fitting is what the switch is threaded onto
  8. corvetteman

    corvetteman Member

    Thanks for all the help. Unfortunately it says R 12 on the compressor so I guess I will have to convert it or can you still get it filled with R 12?
    How would I pressure check the system before I try to refill it? I’d hate to spend the money to have it all leek out.
  9. Chris Miller

    Chris Miller Rockstar 100 Posts

    You can get it filled with R-12, but for the price you might as well buy a brand-new system! :D
    They can vacuum it out and fill it with R-134 for much less, just have to change out the accumulator and orifice tube.
  10. corvetteman

    corvetteman Member

    I found out someone has already switched it over to R134. I picked up a kit and went to add Freon and it seams to be holding pressure, still had to jump the switch to get the compressor to run and still no cold air once running.

    Does this mean the compressor is bad?

    If so how do you go about changing it? just diconnect everything, hook up a new one and refill?

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