2000 Volvo VNL 770 AC Problem please help!

Discussion in 'Volvo Forum' started by ReneJRR, May 8, 2019.

  1. ReneJRR

    ReneJRR Bobtail Member

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    Here is my problem I bought a brand new ac compressor 6 months ago, last month the ac stop cooling for time to time and i mean that it was cooling today perfect and tomorrow blows hot air.

    The mechanic told me the compressor kicks in works fine that the problem was the AC control module that is not starting kicking the compressor and also not stopping the fan it stay all day on with the compressor off, i replaced that module from the volvo dealer and the truck still doing the same thing once the compressor kicks in it will cool the air like it should be.

    Anyone knows why is this happening or what is not letting turn on the compressor when i put the ac in the cabin?

    I appreciate the help in advance!
     
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  3. Bakerman

    Bakerman Road Train Member

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    Check the wires going from the compressor to the module on the firewall underneath the windshield, make sure they are not chafed or grounding out

    Is your module blinking green?
     
  4. ReneJRR

    ReneJRR Bobtail Member

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    The old one was blinking slow green witch means good I bought the new one and is working good too, i will check the wires from the compressor.

    Thanks!
     
  5. Bakerman

    Bakerman Road Train Member

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    As long as you’re not losing any Freon, it sounds like you have an electrical issue
     
  6. ReneJRR

    ReneJRR Bobtail Member

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    It have to be electrical but where is what i want to know lol
     
  7. nasriza

    nasriza Road Train Member

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    Check the freeze switch or thermostat by the blower motor in the evaporator notorious for this kind of problems and in direct relation to compressor working or not.
     
    ReneJRR Thanks this.
  8. ReneJRR

    ReneJRR Bobtail Member

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    Thanks i will look into that, let me ask you something...

    The fan of my truck should not stay on all the time right? I mean if the temp is normal there is no reason to stay on right? Because when the fan stay on all the time the compressor doesn’t kick in so it won’t blow cold air have you seen anything like this?
     
  9. DUNE-T

    DUNE-T Road Train Member

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    Is the fan actively engaged or slowly moving?
     
    ReneJRR Thanks this.
  10. nasriza

    nasriza Road Train Member

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    There is no reason for the fan to stay on, you either have to check the wiring for the module or there is a small chance ac switch for the high pressure is causing the fan to stay on, what is the led flashing on the ac module in the firewall, check to see if its normal operation or something is going on, seems to me like you have a wiring issue going to this module.
     
    ReneJRR Thanks this.
  11. ReneJRR

    ReneJRR Bobtail Member

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    Actively engaged
     
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