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Hvac Control Head On My 02 Silverado Acting Up

Koty

By Koty
in Ask A GM Technician

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Koty Enthusiast

Koty

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Last summer the indicator lights (interior & exterior recirculation, AC) started to come on then go off by themselves (even if the HVAC Control head is in the off position)causing problems in me controlling the HVAC system.When this occurs, if I shut off...then restart the truck it "resets" and works fine then starts acting up again. This problem is intermitant. I did some research and decided that the control head was the likely cause, so I installed a brand new AC Delco HVAC Control head but the problem remained. I've taken my truck to 3 dealers, who couldn't figure out the problem. The most recent dealer tech took the dash completely apart to axcess the pin connectors, checked them all out, put dialelectric grease on em, checked all grounds and said all looked OK. The tech kept the truck running for about an hour and couldn't duplicate the problem......I then asked if I could drive around the streets outside the shop awhile to try to duplicate the problem as it usually occur's after driving a short time, but the symptoms didn't re-occur so I thought that there was probably a chance that the tech had possibly tightened a connector when he checked them out and had corrected the problem. Upon driving home from the dealer.......you guessed it!........starting acting up again.....lights on, off,.... warm air blowing when set to A/C then back to normal. This is driving me nuts!! Do you think that I may have installed a new "bad" HVAC Control module?? Any other ideas?? bad ignition switch??:rolleyes:

IBEW697 Enthusiast

IBEW697

Posted
Posted

hey mike...i had a similar problem on my old 2000 gmc and the A/C had to be recharged. It was tripping a low pressure sensor in the system and causing my lights to flash. I would assume the dealer would've already checked that, though....just a thought.

Koty Enthusiast

Koty

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hey mike...i had a similar problem on my old 2000 gmc and the A/C had to be recharged. It was tripping a low pressure sensor in the system and causing my lights to flash. I would assume the dealer would've already checked that, though....just a thought.

 

Jake.....sometimes all of the indicator lights will come on and stay on, sometimes the lights will come on & go off. It dosen't have to be set to "A/C" for it to happen. lights will even come on when shut off. If this happens & I shut the truck off and restart it will reset and work fine...then start up again. Just curious..... were these your symptoms??

 

Thanks

IBEW697 Enthusiast

IBEW697

Posted
Posted

it has been quite a few years, but i believe they would flash when either the a/c or defrost was turned on. Usually the a/c compressor will cycle with defrost on and i think that is why the light would flash with the defrost. Do you know if the dealership actually checked the A/C system? As far as pressure on the system or electric control circuiting?

Koty Enthusiast

Koty

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it has been quite a few years, but i believe they would flash when either the a/c or defrost was turned on. Usually the a/c compressor will cycle with defrost on and i think that is why the light would flash with the defrost. Do you know if the dealership actually checked the A/C system? As far as pressure on the system or electric control circuiting?

 

 

Don't believe so.......thanks, this is another angle to look at.

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