On my 91 silverado hot air blows in constantly when i am driving even if the heater is off i got another circuit board from a junk yard for the heater controls and it still does the same thing but now when i put it on a/c the display "A/C" flashes so i put the original circuit board back in and it stopped flashing and the a/c works i will check to see if the mixing box is behind the glove box and check to see if it is operating correctly. Also my friend told me that the cables r probably seized and need lubricated/replaced what are your thoughts on this if anyone can help thank you very much

 

Hi, I didnt want to start a whole new thread for something that is already in circulation so hopefully this is still new enough to grab some eyes...

I have an 02 gmc sierra 1500 SLE 5.3 v8 4x4.. My problem has been narrowed to 1 of 2 things.. the dash unit for my climate control has gone bad, or the actuator (spelling?) that controls the flaps are bad.. I have a great working AC system.. but the air only comes out on the windshield/feet/back seat. I have been told that the 2 most common problems are the only two things it could be by the guy at the dealership working the parts counter.. The dash unit shows my air at the "dash setting" but no air comes out.. and he said that the selector could be bad OR the gears in the actuator have gone out.. so here is my REAL dillema.. I live in Az where 115 degrees is everyday common... I have a 5 year old I need to get around with and I cant be without ac.. I tried to get into my dash to check the actuators but I cant figure out how... any help would be great : )

 

If you can find the blend door, use a test light to see if power is running to it. If not then it is the HVAC.

 

I dont mean to sound totally ignorant but where would I find that? Underside of the driver or passanger? Or is it somewhere totally different? My dad had told me that their old GMC Yukon's dash had like 4 or 6 bolts that he could undo and the whole dash dropped forward to get into it.. IDK what the heck he is talking about either..

 

Never mind.. I found my actuator and that is the problem. thanks for the help : )

 

Good deal! Sorry I couldnt get back to you sooner, was out of town.

 

np.. just took me 2 hours of pulling my dash apart to realize that I didnt have to take anything apart at all : ) makes you feel real smart when it finally pops out at ya.. good thing it wasnt a snake.. or Id be ded.. Lol

 

Lol I've had my moments too.

 

Hey, I have an 05 GMC Sierra SLE and it sounds like I have the same problem you had. Also one of the work trucks I drive is doing the same thing. Where I live the climate is getting cold (below freezing some times) and I have my dual climate controls set to about 68 deg. I'll be driving for a while, everything is up to temp and all of a sudden I'll feel really hot air blowing out of the dash vent on the drivers side. I'll feel the passenger side and it's a lot cooler. both sides are set to the same temp. Can I ask you what you did to access the door actuator?

 

Silverado 2005. I had the problem where the blend door shifts on its own and blows hot air out the driver side. I replaced the blend door actuator twice - the second time with a GM part. It worked for 2 days and then went back to intermittent shifting. Usually it just shifts to hot and stays there a day or so and then blows cold on start-up the following day. Yesterday, on a 10 minute drive it shifted cold to hot to cold to hot and then stayed.
Is there something beside the blend door actuator that needs replacing? I was wondering about the control panel on the dash. Someone on this thread mentioned the A/C cycle switch and/or the circuit board.
Any help will be appreciated. I don't know where to find the cycle switch or the circuit board.
Thanks.