Hvac controls power supply

Discussion in 'Audio + Electronics' started by Sam G, Jan 19, 2020.

  1. Sam G

    Sam G Newbie

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    845AA10E-396D-4598-912A-D8FC66F41D1E.png DD3E965F-5172-4BAA-991B-E7B91B908530.png Hey everybody this is my first post and it seems like there’s a ton of knowledge on this forum so I’m hoping someone can help me out. So anyways I have a 91 k1500 and the heater control hasn’t worked since I’ve owned the truck. Yesterday I went out and started poking around to see if I could figure out what was wrong with it. I pulled the center section of the dash and glove box out and found the three wire plug that would receive power for the unit hanging loose not plugged into anything. The other side of the plug that would feed this with power is nowhere to be found. I’m figuring I’ll just cut that plug out and splice in my own plug in connectors but I’m hoping someone can clarify which wire receives what. I’m assuming the red wire gets 12v, the black wire goes to ground, and I’m not sure what the third yellow wire would be. Can anyone tell me if my assumptions are right or wrong and what the third wire would be?
     
  2. RawbDidIt

    RawbDidIt I'm Awesome

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    From what I can find on three Google machine it looks like that plugs into the convenience center. As for which wire goes where, you're probably correct, but take a look at the wires and see if there's a short. I have no idea why the PO would disconnect it, but if they couldn't figure out an electrical problem, I can see somebody just leaving it disconnected until they have time to figure it out.

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  3. Donald Mitchell

    Donald Mitchell I'm Awesome

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    Mines a 1990 but I think these are the same wires. One side comes in from the firewall and the other in goes into the computer harness. Also here's a video where you can see the wires.
    HPIM0952.JPG
     
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  4. Sam G

    Sam G Newbie

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    Yep that plug in the picture is definitely what I’m looking for. My problem is the bottom half of that plug coming out of the harness isn’t there. I’ll take another look and see if I can find anything that was cut.
     
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  5. evilunclegrimace

    evilunclegrimace Does not always play well with others

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    I am pretty sure that plug does not power the AC control head, I just swapped the dash out in my '91 and can get a pic of the correct plug if you would like
     
  6. evilunclegrimace

    evilunclegrimace Does not always play well with others

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    This is what the plug for the Heater/AC head looks like ; IMG_2303.JPG IMG_2303.JPG

    IMG_2302.JPG
     

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