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Engine cooling fan always on when running, a/c-recirculation 3 blink

Discussion in 'Engine & Drivetrain' started by tomustang, Jun 21, 2020.

  1. tomustang

    tomustang Member

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    Engine temp is fine, a/c ran super cold 1 day ago.

    Day later I started the car, 85° outside, noticed the cooling fan started running, once I got into yukon I tried the a/c and the light blinked 3 times and shut off, same happened with the recirc. I tried the other controls and the only selection that works is Auto. The defrosters work fine but can select anything besides Auto.

    All air that comes out of vents is hot.

    I cannot find any other search inquires that deal with engine fan constantly running and the AC / recirc blinking.
     
  2. tomustang

    tomustang Member

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    Update.


    I ran a 12 power source to the a/c compressor while the motor was on, the clutch engaged and i got cold a/c.

    AC and recirc button still flashing 3 blinks, assuming now that the wire going to the AC compressor is bad and the engine is reading that it's non-functioning so the high-speed fans are running.

    Freon level was full, thermostat is new, coolant sensor on block is new. A/c sensor on canister is new. A working relay was checked and got nothing.

    I'm going to trace the wire to see if there's any breaks in the line.
     
    thompsoj22 and donjetman like this.
  3. thompsoj22

    thompsoj22 Full Access Member

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    There are alot of troubleshooting vids on youtube dealing specifically with your issue and how to isolate it. recently i purchased a "DESLUGGER" from 4 seasons ac to eliminate the compressor slugging which i have experienced twice. our low mounted compressors are susceptible. have you checked for 12 volts and ground at the ac connector to the compressor? simply remove the connector to the compressor hook up your meter and cycle ac on/off. the pressure switch on the dryer will also prevent ac clutch engagement.
     
  4. tomustang

    tomustang Member

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    Since you said the compressor plug, I just checked it both with running and not and I get no power. The relay side is fine.
     
  5. Joseph Garcia

    Joseph Garcia Supporting Member

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    The three blinks of the AC light indicates that the AC mode is not available.

    From the owner's manual:

    #(Air Conditioning): Press this button to turn
    the air conditioning (A/C) compressor on and
    off. When air conditioning is selected, an indicator
    light will come on to let you know that the air
    conditioning has been activated.
    Pressing this button when the outside temperature
    is too cool for air conditioning will make the air
    conditioning indicator flash three times and
    then turn off to let you know the air conditioning
    mode is not available
    . If the air conditioning
    is on and the outside temperature drops below a
    temperature which is too cool for air conditioning
    to be effective, the air conditioning light will turn off
    to let you know the air conditioning mode has
    been canceled.

    I recognize that the too cold outside air scenario is not your current scenario, but you may be able to troubleshoot the system to see what other conditions could make the truck's computer think that it is too cold outside.
     
  6. scrtcell

    scrtcell TYF Newbie

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    Hey I know this may sound like a long shot and some things may not seem so obvious only because I have seen this before but is the belt missing that drives only the compressor ijs
     
  7. tomustang

    tomustang Member

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    I ended up testing on them both yesterday, I swapped them around and I still had outside temperature readout so I know they're both fine.
     
  8. tomustang

    tomustang Member

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    There's a new belt on it, I've already jumped the compressor with an outside 12v source and it blows cold air inside
     
  9. tomustang

    tomustang Member

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    I've bought another AC sensor to see if the other one was bad.


    Does anyone know if they're supposed to be constant power going to the AC compressor, because I'm not getting any juice, I don't know if the reason why the fans are on if it's cutting the power to the compressor or not
     
  10. swathdiver

    swathdiver Full Access Member

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    How do you know that the refrigerant level is fine? What are the internal trouble codes? What are your low and high side pressures at idle?
     
    Joseph Garcia likes this.

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