The A/C clutch engages when the vehicle is turned off?

1991 CHEVROLET 1500
300,000 MILES • 5.7L • V8 • 4WD • AUTOMATIC
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RBSMITH1015
  • MEMBER
  • 1 POST
The A/C clutch engages when the vehicle is turned off draining the battery.
I can disconnect the A/C cycling switch and it will disengage. I replaced the cycling switch thinking that was the problem, but I was wrong. I put a test light on one side of the and there is power to it even though the vehicle key switch is off.
Aug 18, 2022 at 2:36 AM
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STRAILER
  • AUTOMOTIVE REPAIR CONTRIBUTOR
  • 54,178 POSTS
It sounds like the HVAC control module has gone out. here is the wiring diagrams for the system so you can see how it works and I have included how to change the module out in the images below. Check out the diagrams (below). Let us know what happens and please upload pictures or videos of the problem.
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Aug 18, 2022 at 11:20 AM
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