HVAC CONTROL MODULE QUIT WORKING

  • Tiny
  • zpainter1015
  • 1992 GMC C2500
  • 226,000 miles

The electronic hvac control module in my truck just shut off driving. I replaced it with one from the salvage yard, didn't fix it. Used a volt meter and tested power wires, the battery and ignition power are fine. The main ground shows good but the second shows bad. Don't know where this ground goes or if it even if it would effect the module. Hot here and don't have a/c.

Sunday, August 28th, 2011 AT 2:49 AM

4 Answers

  • Tiny
  • Jacobandnickolas
  • Expert
  • 68,287 posts

The ground could be under the dash. I would recommend running a new one.

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Thursday, September 1st, 2011 AT 3:00 AM
  • Tiny
  • zpainter1015
  • Member

Ran a new ground module came on and worked. Then smelled a burning smell and blower quit and won't work on any setting. The blend arrow lights are also now flashing.

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Sunday, September 4th, 2011 AT 1:30 AM
  • Tiny
  • Jacobandnickolas
  • Expert
  • 68,287 posts

Check to see if there is power to the blower motor. There must be something causing things to overheat. The original ground may have melted.

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Sunday, September 4th, 2011 AT 1:49 AM
  • Tiny
  • zpainter1015
  • Member

Had the old control module out of truck so put it back in and blower worked for a little while then quit. Found on circuit board that one of the connectors is burning the solder. It's is a black wire in slot 9 on connector. Wiring diagrams don't show any wire there.

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Tuesday, September 6th, 2011 AT 10:20 PM

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