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1999 trans am compressor issue. Weird

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  • 1999 trans am compressor issue. Weird

    Comp clutch went bad then installed reman comp. A.c.comp. will work as long as idling. Drive and it shuts off after couple minutes. Turn off car and restart a.c. will work again. Pressures are within spec. Changed pressure switch. Same. Checked connections. Any other ideas.

  • #2
    With a re start the problem goes away, sounds like a computer issue. Most new stuff has a micro controller to run the heat/ac system. Good luck!


    • #3
      Don't think there is a computer control for climate. Thanks though


      • #4
        Ok, then post some pressures both at idle and at speed (2000 RPM) and we'll go from there. The fact that re-sets says more likely electrical than mechanical.


        • #5
          Looked on Rockauto to see what kind of switch it has, and there is no "Trans AM" list for 1999? Grand AM is but no Trans AM?
          I guess a Trans am would be a trim code on aa Firebird.
          Under Firebird listing there is a 3 terminal "pressure sensor" for the A/C which means there is a computer involved, somewhere. My guess is it is sensing pressures out of wack an shutting the system down.
          Not my strong suite by any means but there is more going on than just an electrical switch.
          Lets go back to basics with some pressure readings.

          Was the refrigerant measured back in by weight? Close is not good enough on some of these newer systems. The fact it has a pressure transducer and not a simple switch means there is an ECM somewhere monitoring everything and making judgements on what it "sees"
          We recently had a Nissan Rouge that was having problems, and was able to find a manual on line. Cut-out pressures were dependent on engine RPM! It is possible to have it take into account, road speed, altitude, outside air temp, engine rpm and the list goes on. It is just up to the engineer who designed the system. It can base its algorithm for if the system is working correctly by looking at engine RPM, road speed and high side pressure and decide if it is within acceptable perimeter or not, and lock off the systems if it detects something outside what it should be.
          Again given the fact it re-sets on a re-start, I think you have a ECM locking off the system.
          Last edited by Cornbinder89; 07-11-2018, 01:24 PM.


          • #6
            Hmmmm? I'm not looking it up till we hear back. Either way check the dang air gap with a feeler gauge just because. Then just how did your recharge this and know you aren't way too low or high? Pressures at least when it does stay on as Cornbinder89 already suggested is a must too know. BTW remans have a horrible reputation or maybe just me just plain never go that route if new is available and should be either car,
            MetroWest, Boston