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HVAC Module


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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.

 
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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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