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A/C Heater Control Problems


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Texas Shoe's Avatar
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October 27th, 2010, 9:53 PM   #1  
A/C Heater Control Problems

On my 2004 Silverado 1500 4 dr. I have recently experienced a problem dual cool/heat control with the drivers side control (cool/heat) that does nothing (stays cool always) and passengers side control (cool/heat) that goes to full heat at the 3rd click from maximum cool. I suspect either control mechanism in dash or at least (1) defective HVAC heater blend door actuator (driver side) and maybe (2) with the (passengers side) also. Is there a way I can observe either (visually, electrically, etc) or check this before I have to disable my truck to remove and replace parts? Also what is the best way to get at these parts if they are bad? Local dealer wants to keep my truck for a day to check it and still can't guarantee it repaired the same day. Any insight on this problem or a link to a previous thread would be appreciated.

 
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October 27th, 2010, 11:26 PM   #2  
I'd have someone look at it and find out what the problem(s) are, electrical stuff can be tricky. Salvage yard is where I'd get the parts, I needed a new fan motor and the dealer wanted something like $200, aftermarket is was about $120, the salvage yard wanted $35. If you need to replace climate controls in the dash, it's simple to do. Everything is basically plug and play with 2-4 screws holding it there. I know the blower motor resistors are cheap and tend to go a lot, but I doubt thats your problem.

 
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October 28th, 2010, 10:08 PM   #3  
Blend Door Actuator

I found this on the forum that may prove beneficial to possibly trouble shoot this issue with my blend door actuator. Might have someone else out there with the same issue. More info is better. I am going to continue to look as I still am not sure if this is the problem or how this device is calibrated after installation.
Link below.
http://www.chevroletforum.com/forum/...+door+actuator

 
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October 29th, 2010, 1:16 PM   #4  
I've got a similar problem with a 2005 Silverado crew cab, dual zone. at random moments the air on drivers side switches from cold to hot for a period of time, and then back to cold. At first I thought freon / compressor or other issue, but then I noticed the passenger side stayed cold throughout. Usually I just wait it out, as it's only a minute or two, but twice now -- I've had to turn system off for 15/20 mins before it fixes itself. Which do you think -- Blend door or actuator?

 
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November 7th, 2010, 8:36 PM   #5  
a/c heat control i.e. blend door actuator

SRWOOLC WROTE "I've got a similar problem with a 2005 Silverado crew cab, dual zone. at random moments the air on drivers side switches from cold to hot for a period of time, and then back to cold. At first I thought freon / compressor or other issue, but then I noticed the passenger side stayed cold throughout. Usually I just wait it out, as it's only a minute or two, but twice now -- I've had to turn system off for 15/20 mins before it fixes itself. Which do you think -- Blend door or actuator?"
Texas Shoe replies - My 2004 actually did the same thing about a year before the current issue appeared. Mine straightened itself out until now. I look around using search for every wording I could think of related to the problem. There was a post that I linked to in a previous reply. The post talks about leaving the fan off and turning key on and listening for the actuator to move. My drivers side actuator was doing nothing. Actually it is quite simple for the drivers side "blend door actuator" on the dual air controls. Before shutting everything off after testing first place fan in off position and cool/heat in cold position, turn off key and remove negative post on battery, I will explain further in end of post. Then (1) Remove the cover over the bottom of the vent system, 4 screws total, use a 9/32" socket, I used an inspection mirror to locate them all. Once removed you kind of have to work it out. (2) Drivers side actuator is on bottom of vent system above right side of trans tunnel, 1 electrical clip connector and 2 screws 1/4". Remove the actuator and it may require a little effort (mine was stuck in cold which applied pressure to shaft. After actuator is clear (3) reach up and manually exercise the door actuator. Mine had free movement open and closed. (4) Go to your local parts store and purchase a new actuator. (5) Replace the actuator (they come in center position) so you will have to move the door shaft to match actuator. (6) hook up the wire harness to actuator and then hook up your battery. (7) Turn on key only and observe movement of actuator. Mine went from center to full one direction and then reversed to full other direction and then settled a minimum heat position. I then exercised the controls and observed correct movement. Replace cover and you are done. Note: somewhere I read that the actuators go through a calibrating process every time power is removed from system, hence why battery was disconnected. Somebody else might know more about this, but it worked for me. I had talked to a shop and they were talking about some kind of analyzer and calibration processes after changing the actuator. FWIW this worked for me.

 
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October 10th, 2011, 10:53 AM   #6  
my 2004 cheve silverado pick up with duel Ac/heat levers. with A C running and blowing cold will chaNGE TO HOT AIR ON THE LEFT SIDE. While the right side continues to blow cold air. If i stop and tour of the engine and restar it, then the Ac will blow cold on both Right and let sides.. What is the fix for this common AC problem?

 
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December 11th, 2011, 1:47 PM   #7  
2005 driver blend actuator

My 2005 was easy to get to and remove, right on bottom. Took it apart and the motor worked on a 9v battery and is good. I manually moved door to heat and am good for the winter. Wonder how to tell if it is the actuator bad or the controller? May do some swapping in a friends to see if my actuator moves. Well, at least we aren't freezing now!

 
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December 15th, 2011, 12:12 PM   #8  
I have a 2003 Silverado LS with dual manual climate controls. There is a service bulletin/recall (whatever they are called) on the wiring harness. The harness connector fails and the dealership has to repair it by splicing a new connection in. Try to look at that.

My AC and heat controls have totally failed on me twice and both times it was the harness. Out of curiosity, when my AC failed this summer, I bought brand new GM OEM controls off ebay for $80. Took all of 3 minutes to put it in the dash. After install, the vehicle has a default setting it needs to get to with the controls so I was told (by dealership) to leave the controls alone, after sending power to new unit, for 5 minutes.

THe blend doors are a known problem for the trucks. The door gears are acutally plastic and over time they turn to jello...that's what the Chevy Dealership mechanic told me when they replaced mine this year. My passenger side door still makes noise and wont' open if the passenger climate control is all the way down on cold. I have to move it up 2 clicks.

The blend door issues take some time to diagnose (I stayed and watched them do mine) so try not to get impatient. I usually test drive some cars/trucks while waiting. :-)

 
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March 21st, 2012, 1:09 PM   #9  
A/C issues

I read your post about disconnect the battery to get the A/C and heater controls working again ,Ive done that several times, and the unit comes back with other characteristics still not functioning right either no cold air and or levels not coordinating or both {read on please} , I spent about $200.00 dollars on the A/C my 90 K1500 last summer! and when I wanted the heat it started acting up !! check the small survo motors, they seem to do what there suppose to do except when you would try to get the dash vents to stay in one position it would travel right past the dash on to the floor with out stopping, now the only feature I can get is hot air to the windshield ,and the dash control panel arrow indicators blink, both the vertical and the horizontals,so I guess the question I'm asking is the instrument control panel or the servo motors giving me fits??? [[[90 chevy silverado ASM H/AC control panel, the unit I'm looking for has a recycle button were most that I've seen have a MAX air button I need the one that has a the REC button!!!! the way I under stand it the one with the MAX is not enter changeable correct me if I'm wrong]], please advise Steve; is there a way that just run cables to the levels and hot and cold doors and bi pass the electrics

 
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August 19th, 2012, 11:26 PM   #10  
I am going thru the same prob now w/a 2004 Avalanche, blows cold for a min or two then goes to hot air on driver side, and also have a problem w/th fan motor continuing to run when the I kill the engine and remove the key! the a/c blower fan just continues to run!!! I have pulled the relay fuse under the hood for the time being to kill the fan motor, but have no clue what to do about the hot/cold issue...it started immediately after I changed batteries...HELP???

 
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