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06 GMC Sierra drivers side A/C blowing hot air


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gdog
Novice

May 23, 2010, 6:12 PM

Post #1 of 16 (10769 views)
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  post locked   06 GMC Sierra drivers side A/C blowing hot air  

A/C usually works fine, however, without notice the drivers side A/C vents will blow only hot air, despite the temp controls being all the way to cold. Passenger side continues to work fine when this happens. If I stop the truck and turn off the ignition and re-start engine, the A/C will then again start working fine until, without notice the same thing happens again. Any ideas?


Hammer Time
Ultimate Carjunky / Moderator
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May 23, 2010, 6:18 PM

Post #2 of 16 (10763 views)
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  post locked   Re: 06 GMC Sierra drivers side A/C blowing hot air [In reply to]  

The heat in that vehicle is controlled by blend doors that regulate heated air flow. They is operated by an electric motor/actuator. The problem can be that the actuator is stripped or inoperative or the door itself could be damaged. This is what needs to be determined by examining the actuator for that side and see if it is responding to heat change commands or not.




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We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.



gdog
Novice

May 23, 2010, 6:53 PM

Post #3 of 16 (10758 views)
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  post locked   Re: 06 GMC Sierra drivers side A/C blowing hot air [In reply to]  

Any idea how long a dealership will take to trouble shoot something like this and what the damages might be?


Hammer Time
Ultimate Carjunky / Moderator
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May 23, 2010, 7:20 PM

Post #4 of 16 (10755 views)
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  post locked   Re: 06 GMC Sierra drivers side A/C blowing hot air [In reply to]  

It will probably take them about an hour to diagnose the problem. It depends what they find to determine what the repairs will entail.




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We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.



Tom Greenleaf
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May 25, 2010, 7:22 PM

Post #5 of 16 (10743 views)
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  post locked   Re: 06 GMC Sierra drivers side A/C blowing hot air [In reply to]  

gdog: One thing of a few that can cause that is evap icing. Will the vehicle make condensate (water) dripping which is normal unless remarkably dry air. Diagnostics recommended and pressures with other observations might nail it to something like that. Icing can be from low charge but don't go adding anything till you know,

T
_________________________________________
Long retired now


gdog
Novice

May 26, 2010, 5:59 PM

Post #6 of 16 (10725 views)
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  post locked   Re: 06 GMC Sierra drivers side A/C blowing hot air [In reply to]  

Thanks for the replies. There is water dripping from condensation so does that mean it's not likely the icing issue you spoke of? It did it again today after driving for about 20 minutes. At a stop light I shut the vehicle off, restarted it, and the AC worked fine for the rest of the 30 minutes I had to drive. My fear is that once I get it into the shop they won't be able to get it to act up or diagnose unless it actually happens while they are looking at it.


Hammer Time
Ultimate Carjunky / Moderator
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May 26, 2010, 6:02 PM

Post #7 of 16 (10720 views)
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  post locked   Re: 06 GMC Sierra drivers side A/C blowing hot air [In reply to]  

Icing would effect both sides and you would have very little air flow so I doubt that. It would also not come back immediately just by cycling the key.




~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.



gdog
Novice

Jun 26, 2010, 8:10 AM

Post #8 of 16 (10655 views)
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  post locked   Re: 06 GMC Sierra drivers side A/C blowing hot air [In reply to]  

Haven't had a chance to have original issue diagnosed yet but wanted to bounce one other gem out there to see if anyone knows if this makes a difference. I have further discovered that the driver's side warm air issue also occurs when I'm using "vent" only setting without the A/C on at all. In other words, when it is cool enough outside not to run the A/C and I have the console set to vent outside air in, it will also intermittently switch drivers side of the vented air to blowing warm/hot air and again adjusting temp control makes no difference. During this time the passenger side continues to deliver the cooler outside air to the cab. Once again, shutting the vehicle off and restarting, will at least temporarily correct the issue. Any idea if this moves the potential diagnosis away from an A/C issue to more of a vent switch or other issue?


Hammer Time
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Jun 26, 2010, 8:20 AM

Post #9 of 16 (10653 views)
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  post locked   Re: 06 GMC Sierra drivers side A/C blowing hot air [In reply to]  

Same answer




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We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.



Tom Greenleaf
Ultimate Carjunky / Moderator
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Jun 26, 2010, 8:55 AM

Post #10 of 16 (10648 views)
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  post locked   Re: 06 GMC Sierra drivers side A/C blowing hot air [In reply to]  

I'd say this does take the "cooling" effect of A/C out of the equation.

One question we have to rule out now is does this by any chance have dual zone climate control? That would change the whole game now.

Basics: The flow goes thru a rectangle of heater core and evaporator. If one side of the rectangle is warmer or cooler depending on requesting heat or A/C the driver's side suffers first in most cases. In vent mode or any request that allows direct outside air only thru the system it's a diverter door that directs it and another directs where - floor, panel, or defroster ducts. Another blends the air no matter where from either recirculate or fresh only. That actuator may have an attitudeMad. There's a chance that the door/flap itself has some issue but that isn't so consistent with it behaving after being shut down for a while??

Generalities - meaning most vehicles: When you shut the vehicle off most will default to a "home" position and ducts may be on defrost and my guess is most would shut down outside air but not sure. Seems a bit new to me by the year of the vehicle but sometimes the pivots of those doors will wear their pivot hole where they fit in the distribution box for all this stuff out and initially you get a funky behaviour and we seem to have that here. I'd sooner blame an actuator that is struggling, part stripped out OR perhaps a rod(s) that are frequently used to remotely turn those doors has a failure. Some older GM and maybe this one used a spring cushion in-line of those rods so you don't get a 'slamming' sound of them moving. If plain broken so far I've found it's from trauma from doing something else in the area.

More: Many designs the heater core is constantly flowing engine temp coolant all the time and this may be one of that design. The system blocks that totally or partially depending on request.

I'm still wondering why the driver's side gets the bounty of heat but not the A/C? The length of ductwork is naturally longer to driver's side and influenced by higher under dash hidden heat that still makes it there from engine heat.

So far I'm blaming the blend door - itself, the actuator thereof, rods if used to control it, or the pivots (usually holes with rod thru them) to be the cause.

BTW - Hammer may not be back till Monday. Ideas from anyone welcome but I think this may take some hands on inspection to watch the action of the associated parts operate to see what may not be moving far enough and why,

T
_________________________________________
Long retired now


gdog
Novice

Jun 26, 2010, 10:40 AM

Post #11 of 16 (10641 views)
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  post locked   Re: 06 GMC Sierra drivers side A/C blowing hot air [In reply to]  

This 06 GMC Sierra does have dual climate zone controls. When it has gone into this "blowing hot air" mode while at idle, I've been able to hear a slight change in the engine rpm, much like you might feel/hear when the compressor kicks on or off when the A/C is on. When blowing hot air, if I adjust the hot/cold slide for the driver's side or zone, there is no difference in temperature coming out the driver's side, it seems to keep the same temperature. At the same time, while the driver's side is doing this, I can adjust the passenger's side climate control and it will go from cool to hot when I adjust the passenger temperature control. Again it only takes a momentary shut down of the engine with an instant start and it generally corrects the problem. Sometimes it will then operate correctly for the rest of the trip, other times it will revert to the problem within a few minutes, with no consistancy/pattern of when or why it occurs.


Tom Greenleaf
Ultimate Carjunky / Moderator
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Jun 26, 2010, 11:36 AM

Post #12 of 16 (10638 views)
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  post locked   Re: 06 GMC Sierra drivers side A/C blowing hot air [In reply to]  

Arggh! Wish they wouldn't do that in vehicles. That over complicates what is as dumb as shutting a vent with your finger as I see it. No matter the problem is there and the extra blend door (must have it by the concept) is getting wrong input info OR isn't moving properly.

Could the control head be the issue - maybe. Not much help now as I've never worked on one of those and the plain ones are tricky enough. Stay here for more help than I can suggest now but I'd also make a summary as it's now pretty well understood what is happening which is heat is NOT quitting on driver's side on a dual zone system.

I suggest you also bring this to another site at the link below...........

http://acsource.net/...644d7d8eeeb77edc058a

They are strong in GM and many from SW USA and Mexico where A/C rules.
It's a sign up site like this one. That is just to keep the spammers out. It's privately owned which is becoming rare out there with no ads and still free to use!

Also because this is so relatively new check for warranty! Yes - even if over on miles or the original time some vehicles come with full five year for A/C no matter the miles or what you might have thought it had.

Do note any recent dash work, radio type installations, anti-theft items aftermarket or installations that involved the dash.

This could be a dumb as some connection to check or a complete dash removal to remedy. I simply don't knowUnsure

T
_________________________________________
Long retired now


Hammer Time
Ultimate Carjunky / Moderator
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Jun 26, 2010, 7:08 PM

Post #13 of 16 (10634 views)
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  post locked   Re: 06 GMC Sierra drivers side A/C blowing hot air [In reply to]  

My money is still on the blend door actuator or blend door itself for that side.




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We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.



ATalley
New User

Jul 18, 2010, 8:44 PM

Post #14 of 16 (10508 views)
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  post locked   Re: 06 GMC Sierra drivers side A/C blowing hot air [In reply to]  

My 05 had same problem, lost memory from computer after battery change out. Took it to dealer to recode. Sometime you can move dual control to full heat, turn off engine, leave over night, turn engine on first. then switch both controls to full cool.


dcraiga
New User

Jun 15, 2012, 1:06 PM

Post #15 of 16 (6726 views)
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  post locked   Re: 06 GMC Sierra drivers side A/C blowing hot air [In reply to]  

I have an 04 GMC Sierra pickup that does exactly the same as what you described above. The odd thing is, when it is not in the unsolicited "heat mode" the controls for driver and passenger work fine. Another thing is that usually, my truck will put out the heat in the first couple of miles after starting the vehicle, then, after I do stop and restart the truck, I can usually drive on without an additional reoccurrences of the heat coming on by itself. Was hoping to find someone who has had the same problem, and has had it repaired and who knows what was really done to repair it.


Hammer Time
Ultimate Carjunky / Moderator
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Jun 15, 2012, 1:08 PM

Post #16 of 16 (6723 views)
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dcraiga
Please don't respond to old questions. This one is 2 years old





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We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.





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