Dual Climate Mishaps

TexasEdition · March 5, 2010

I have an 04 GMC Sierra 1500. I've noticed that every once and awhile my driver side A/C will start blowing hot air. This is very random and happens when I'm running just the vent or cold A/C. Is this something I can fix on my own? I can move the hot and cold switch up and down, but it never makes a difference, and it's always my driver side that does this.

jrrod2004 · March 5, 2010

Manual HVAC or Auto HVAC?

jro909 · March 5, 2010

manuel he said move the climate up and down...its a common problem with the vent doors

TexasEdition · March 5, 2010

Any fix to this?

TexasEdition · March 8, 2010

Well, I tried to looked behind to see if anything was burned or broken behind the A/C cover in the truck. I unplugged the unit and worked on a short in one of the bulbs and when I plugged it back in and started things up, and now I only blow air through the windshield vents. My knobs don't work if I put it in any other setting. I'm very upset know, because all I did was unplug the unit and plugged it back in. Please help. I have a long trip (800 miles) in a few days. I just want it working correctly again.

jrrod2004 · March 8, 2010

Well, I tried to looked behind to see if anything was burned or broken behind the A/C cover in the truck. I unplugged the unit and worked on a short in one of the bulbs and when I plugged it back in and started things up, and now I only blow air through the windshield vents. My knobs don't work if I put it in any other setting. I'm very upset know, because all I did was unplug the unit and plugged it back in. Please help. I have a long trip (800 miles) in a few days. I just want it working correctly again.

Did you resolder anything? Did you move the knobs at all? I recommend that you disconnect the battery and plug it back in. This may help the "brain" of the HVAC controls reset. Also, check to see if any fuses are blown - you never know. Did you ever check the vent doors?

TexasEdition · March 8, 2010

Well, I tried to looked behind to see if anything was burned or broken behind the A/C cover in the truck. I unplugged the unit and worked on a short in one of the bulbs and when I plugged it back in and started things up, and now I only blow air through the windshield vents. My knobs don't work if I put it in any other setting. I'm very upset know, because all I did was unplug the unit and plugged it back in. Please help. I have a long trip (800 miles) in a few days. I just want it working correctly again.

Did you resolder anything? Did you move the knobs at all? I recommend that you disconnect the battery and plug it back in. This may help the "brain" of the HVAC controls reset. Also, check to see if any fuses are blown - you never know. Did you ever check the vent doors?

I did not resolder anything. I may have moved the knobs after the unit was taken off. I did disconnect the battery for a few minutes (just the negative terminal). Plugged things back in and I have the same problem. I will check the fuses once more. How do I check the vent doors? All vents are open on the dash if that's what you mean.

jrrod2004 · March 8, 2010

I did not resolder anything. I may have moved the knobs after the unit was taken off. I did disconnect the battery for a few minutes (just the negative terminal). Plugged things back in and I have the same problem. I will check the fuses once more. How do I check the vent doors? All vents are open on the dash if that's what you mean.

No, I meant actuator doors. I will have to pull some diagrams that are stored on my home PC and try to show you.

TexasEdition · March 8, 2010

That would be great. Are there reset procedures to fix this. Only reason I ask is that I heard of people doing this. Not sure if this will help me.

jrrod2004 · March 8, 2010

That would be great. Are there reset procedures to fix this. Only reason I ask is that I heard of people doing this. Not sure if this will help me.

Truthfully, I cant remember on the reset procedures. I will search for it and get back to you when I get home.

TexasEdition · March 9, 2010

I disconnected the battery again and let it sit for about 15 minutes then let things boot up again and everything is back to normal. I still have the original problem, but I guess I can live with that better than just having hot air coming out of my dash vents. So............it one of those days for me. Upon reinserting my A/C control unit I noticed that the defrost button doesn't work. I lost the rubber grommet that fits on the inside of the unit that helps turn it on. Now I don't know what to do about THIS problem. Any solutions? I've look everywhere for that stupid thing. It's the black nipple looking thing that helps turn on the defrost button.

pm26 · March 9, 2010

And I thought that this thread was about global warming.........

jrrod2004 · March 9, 2010

Some PDFs that might help:

Files removed...

havo · March 9, 2010

I had an 04 Denali and both of the actuator doors went out at one point or another, causing AC on one side and heat on the other... when it's 105F outside, I couldn't tell if it was heat or if it was ambient outside air

TexasEdition · March 9, 2010

I had an 04 Denali and both of the actuator doors went out at one point or another, causing AC on one side and heat on the other... when it's 105F outside, I couldn't tell if it was heat or if it was ambient outside air

I understand the pain. Now I have the driver's side ALWAYS blowing hot air. It used to be just random. What can I do? I still haven't found an answer. Should I just take it in to the dealer or local mechanic?