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  1. #1

    Default A/C wiring question

    Let's see if any of you have had this same problem occur.....

    Car is a 1984 GT Vert. Stock wiring harness

    Been trying to get A/C going.....system was converted to 134A years ago.

    I put in all new A/C components (Compressor, Condenser, Evaporator, etc.) here recently

    Went to jump low pressure switch plug with A/C switch on dash turned on and compressor did nothing. I found the WOT switch plug and installed jumper wire then the clutch kicked on. When I went to take jumper out of low pressure switch plug the compressor kept running. Turned off A/C switch on dash and the compressor still kept running! It would not shut off unless I pulled jumper out of WOT switch.

    Has anyone ever encountered this? Or have any insight as to what could be going on?

  2. #2
    FEP Senior Member Tigger's Avatar
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    I would verify that the dash switch is working properly. Might be on all the time? If that checks out good, I would verify the WOT switch wiring. Something is giving a constant hot to the compressor in order to engage the electromagnet/clutch. Good luck to you
    67 Mustang Coupe
    96 Tangerine GT
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  3. #3
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    FYI, the compressor runs on defrost too.
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    That's a feature. Seriously.

    On some cars at least. For cool humid areas where the inside of the windshield fogs up a lot. Only supposed to run at certain air temperatures which I don't remember.

  5. #5
    FEP Senior Member Tigger's Avatar
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    There should be no power to the compressor circuit when the switch is in the off position. That is what he needs to verify.
    67 Mustang Coupe
    96 Tangerine GT
    86 Saleen #179

  6. #6
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    Tigger, I agree. I was just trying to point out that the compressor running in defrost mode may be normal and shouldn't be the primary concern here.

  7. #7
    FEP Senior Member Tigger's Avatar
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    Quote Originally Posted by darkd0r View Post
    Tigger, I agree. I was just trying to point out that the compressor running in defrost mode may be normal and shouldn't be the primary concern here.
    No worries
    67 Mustang Coupe
    96 Tangerine GT
    86 Saleen #179

  8. #8
    FEP Member SECESH's Avatar
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    Did you jump at the under dash plug where the WOT relay goes? The relay requires a power feed to operate and it could be the clutch is being powered by that circuit. 83 model wire colors to jump are pink/blue and black/yellow. Might be the same for 84

  9. #9

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    I will check the dash switch this weekend. Thanks!

  10. #10

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    Quote Originally Posted by SECESH View Post
    Did you jump at the under dash plug where the WOT relay goes? The relay requires a power feed to operate and it could be the clutch is being powered by that circuit. 83 model wire colors to jump are pink/blue and black/yellow. Might be the same for 84
    Hmmmmm....I think you might be right. I just put a new WOT relay in and when I jump the WOT cut out switch by the compressor the clutch engages whether the dash switch is on or off. Are you saying to remove the relay and put a jumper wire in the plug between the wires you mentioned above?

  11. #11
    FEP Member SECESH's Avatar
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    The jump I mentioned would test the relay, but with a new relay plugged in, the problem must be somewhere else. Power leaving the dashboard control should be on a green with purple spots wire. Possibility that the switch is sticking in the on position. That wire goes out to the pressure switch on the accumulator. You can unplug it there and check if it is always hot regardless of switch position. Keep an eye out for any places where the wires may have been modified.

  12. #12
    FEP Member SECESH's Avatar
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    I've been ruminating on this over lunch. WOT switch at the carb controls the WOT relay under the dash. Power to the clutch is a separate circuit opened or closed by this relay. If engaging this relay by jumping the wot switch powers the clutch regardless of other considerations, then power is getting in from somewhere else other than the proper circuit.
    I need to check a couple of things but I wonder if the relay is the correct one.

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