HVAC Module - Chevrolet Forum - Chevy Enthusiasts Forums
cclingma's Avatar
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May 12th, 2009, 8:04 PM   #1  
HVAC Module

New here, awesome sight.

I found this sight when I was reading on another forum about what to do with my HVAC head/foot/defrost selector switch not working on my 03 Silverado with manual dual climate control. I first removed the actuator but have sense decided it is probably okay as it does run a little when I try to recalibrate the HVAC module. I've tried a few ways of calibration....
1. Disconnect battery for 5 minutes
2. Remove the HVAC fuse under the hood for at least 10 seconds and
then start the truck.
3. Hold the AC switch for 5 seconds, then rotate the selector **** full
one way, then the other, and back again

Each time I try when taking the iginition back to on for the first time after attempting recalibration, the actuator turns about a 1/4 turn and then never turns again. Am I missing something?
Thanks!

 
Mike Sigmond's Avatar
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May 12th, 2009, 8:35 PM   #2  
Welcome to the forum!

I had some warranty work done on my 04 Tahoe about a year ago, they had to remove alot of the dash for the repair they did ( not AC related). When they put it back together my AC did the same thing. I took it back and they said the AC ducts where the actuator is were not sitting right causing the actuator to jam. This may not be your problem but I thought it might help.

 
cclingma's Avatar
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May 13th, 2009, 5:49 AM   #3  
Thanks for the idea. I'll try moving the damper by hand to see if it's free.

 
cclingma's Avatar
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May 13th, 2009, 6:49 PM   #4  
Seems the damper will move manually just fine. I went a little further trying to recalibrate and followed these steps that I found on this sight.
  1. <LI itxtvisited="1">Clear all DTCs. <LI itxtvisited="1">Place the ignition switch to the OFF position. <LI itxtvisited="1">Install the HVAC actuator. <LI itxtvisited="1">Connect all previously disconnected components. <LI itxtvisited="1">Remove the HVAC/ECAS fuse for a minimum of 10 seconds. <LI itxtvisited="1">Install the HVAC/ECAS fuse. <LI itxtvisited="1">Start the vehicle. <LI itxtvisited="1">Wait 40 seconds for the HVAC control module to self-calibrate.
  2. Verify that no DTCs have set as current DTCs.
When I perform the above steps, the actuator will turn about a 1/4 turn and then return to it's starting position when I start the truck. I actually have the actuator uncoupled so that I can clearly see it move. After I wait the 40 seconds and the 1/4 turn business is over I can move the mode selector switch and the actuator never turns again. Any ideas? Is it time to take it to a dealer and have the HVAC module programmed?
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suzuki-guy's Avatar
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May 13th, 2009, 6:58 PM   #5  
First off welcome to the sight and we hope you will enjoy it! Second i would highly advise you to take it to the dealer to have it reprogrammed.

 
Mike Sigmond's Avatar
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May 13th, 2009, 7:38 PM   #6  
Ahhh, I guess its not a physical problem after all, its a mentel problem with the vehicles computer. Thanks for updating us!

Sorry if you took it all apart because of my thoughts, I guess its good to eliminate symptoms first if you can

 
cclingma's Avatar
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May 14th, 2009, 4:19 PM   #7  
Well I broke down and called the dealer. They said they didn't believe there was a HVAC program and said the actuator is probably bad. I'm having a hard time accepting that as the actuator does move when I first start the truck it just won't move with the mode selector switch. I would take it to them but I'm affraid they're going to go pulling the dash out and charge me $700 when I really don't think the actuator is the problem. What would you guys do?

 
Mike Sigmond's Avatar
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May 14th, 2009, 4:20 PM   #8  
ShawnVW might have a good answer for you, lets see if he chimes in, he is a GM tech.

 
maicsa2's Avatar
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July 6th, 2009, 10:20 AM   #9  
I had a Hummer 2 2003, the AC vent control dial is not working, it shows in the computer that it is switching, but the air is coming only on the defrost part (wind shield)
Please help.
My email is maic.salazar@gmail.com

 
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July 30th, 2009, 8:52 PM   #10  
Windshield/Vent/Foot Control

Ditto on the vent control switch with my 2004 Silverado. It only blows out the defroster (windshield). It started acting up after I drained the battery. At first, after the battery incident, it only blew hot air. It has since corrected itself. For a brief second it blew out the vents, and then went back to the windshield.

 
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