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AC clutch not engaging

Discussion in '2nd Gen. Tacomas (2005-2015)' started by spicy12345, Jun 1, 2021.

  1. Jun 29, 2021 at 3:44 PM
    #41
    Jimmyh

    Jimmyh Well-Known Member

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    Yes, I think that is it if it is the one going to the AC Compressor. The Red w/white stripe and White goes to the AC lock Sensor. If you are not getting any voltage when the AC is turned on then it is not being commanded or you have a wiring problem between the relay and the clutch.

    Air Conditioning:
    The A/C amplifier receives various signals, I.E., the engine RPM from the engine control module and coolant temperature from the engine control module, etc. When the engine is started and the A/C SW (A/C control assembly) is on, a signal is input to the A/C amplifier. As a result, current flows from IG1 NO.2 fuse to TERMINAL 2 of the MG CLT relay to TERMINAL 1 to TERMINAL MGC of the A/C amplifier to GROUND, turning the MG CLT relay on, so that the magnetic clutch is on and the A/C compressor operates.

    If the integration control and panel detects the following conditions, it stops the air conditioning:
    ∗Evaporator outlet air temperature is too low.
    ∗There is a marked difference between the compressor speed and the engine speed.
    The refrigerant pressure is abnormally high or abnormally low.
    ∗The engine speed is too low.
    ∗Rapid acceleration occurs
     
  2. Jun 29, 2021 at 3:52 PM
    #42
    b_r_o

    b_r_o Gnar doggy

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    Jimmy what's the wire color that goes from the relay down to the mag clutch?

    Instead of trying to troubleshoot everything at the relay, just go down to the clutch and see if you have power on that wire with the A/C turned on
     
  3. Jun 29, 2021 at 9:14 PM
    #43
    Jimmyh

    Jimmyh Well-Known Member

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    The wire to the clutch coil is Violet.
     
    b_r_o[QUOTED] likes this.
  4. Jul 1, 2025 at 2:20 PM
    #44
    gnuenglander

    gnuenglander Member

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    I have a 2010 4 cylinder Tacoma The AC compressor spins freely without making any noise but the magnetic clutch will not engage. The magnetic clutch does spin freely when I turn it by hand.

    In the past when the clutch has failed I get the blinking AC light in the cabin. The AC light is steady now but the clutch does not engage.

    I read through the blog and here is the testing I have done so far.

    Tested voltage at magnetic clutch relay terminals (inside fuse box under hood) #2 and #5 with AC on: measured 13.2 volts.

    Tested voltage at magnetic clutch relay terminal #3 with AC on: measured 0.0 volts.

    Tested purple wires in two main wire connectors in fuse box with AC on: measured 0.0 volts

    Tested voltage at purple wire socket on inlet side of grey three wire connector atop of AC compressor: 0.0 volts.

    From these findings, can anyone tell me what the next steps in the diagnosis would be and what is the likely failure point(s).

    Thank you very much.
     
  5. Jul 1, 2025 at 2:25 PM
    #45
    Dm93

    Dm93 Test Don't Guess

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    Predator tube steps, Ranch Hand grill guard, Magnaflow CatBack exhaust, Toyota tool box & bed mat, 2LO Module by @Up2NoGood, Rearview Compass/Temp Mirror, Tune by @JustDSM.
    Have you checked if there is refrigerant in the system? A/C Amplifier won't turn the clutch on if there isn't.
     

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