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99 2500 a/c compressor wont turn off!

Discussion in 'Chevy C/K Truck Forum' started by dmuley, Aug 7, 2010.

  1. dmuley

    dmuley New Member

    my 99 3/4 ton trucks compressor wont turn off I switched out the climate control on the dash from a 97 it still stays on all the time, checked the relay under the hood its good. the green wire going to the compressor is hot all the time when the ignition is on it doesn't turn off when the a/c button is pushed on or off like it is suppose to. does anybody have an idea of what could be the problem???????????
  2. Springthing

    Springthing New Member 1000 Posts

    ....bump......
  3. Chris Miller

    Chris Miller New Member

    Seems like your compressor relay might be shorted.
  4. murdog94

    murdog94 New Member 1000 Posts

    Or here is a really really dumb one and dont be insulted, but do you have it on Defrost??? Because your compressor will still run when it is set on defrost and even with the AC off..
    Also i second the relay.
  5. dmuley

    dmuley New Member

    its not in defrost, and I did check the a/c relay located in the fuse box under the hood on fender well its not shorted out, is there another relay for the compressor?
  6. murdog94

    murdog94 New Member 1000 Posts

    Nope just one relay... your climate control box might be shorted out as well. Im not saying it is or to change it but that would be where i would look next. And thanks for not getting offended as i said it wasnt to be a jerk i have just made that mistake when troubleshooting AC before.
  7. Springthing

    Springthing New Member 1000 Posts

    For the price of diagnosis I would go to a salvage yard and pick up another controller module/switch box and see if that fixes the problem. I just got a crash course on these little buggers and I've found out that, at least for my year truck, I'm not impressed with the quality of the controller and it's parts.
  8. dmuley

    dmuley New Member

    I actually already tested the climate control box, i swapped the one out of my 97 and put it in the 99 and the compressor stayed on i also put the one out of the 99 in the 97 and it worked just like it was suppose to. if nobody else has any ideas i guess iwill have to start tracing wires. should i start at the climate swithch where it works fine or at the compressor where the wire is hot all the time?
  9. murdog94

    murdog94 New Member 1000 Posts

    Start where the wire is hot all the time and work back...
  10. dmuley

    dmuley New Member

    thanks!!!!!!!!!!!!

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