Hey everyone tonight i put a tip on my truck and we had to do some welding so i unhooked the batteries just to be safe, all went well until i tried to turn on my air conditioner it came out cold for a few seconds. It then started blowing hot air and wouldnt change temps even if i moved the air temp controlls. The compressor is running the whole time but only hot air comes out. If i shut off the truck then start it back up it will blow cold air for a few seconds then go right back to hot. I dont know what is causing this and would really appreciate and info. Thank you in advance.

idk what this is either. we were welding up a weight bracket on my buddies and we unhooked the batt cables and everything and his started doing this. ill ask him and see if he got it fixed or not, but i was kinda wanderin the same.

That is so odd as that happened to me when my buddy welded my 7 pin connector bracket to my hitch. From what I can recall, I shut it off, then restarted it again. Did this a couple of times. Still had the same problem. So I shut it off for a few minutes, then back on, and it has worked ever since. Maybe some kind of a reset thing? I have the auto a/c vs the slider type if that makes any difference. Jerry.

i've had that same problem. i got an 07 classic and jus the other day was headed out of town and the ac all of a sudden turned hot. its done it a few times but all i do is turn the whole truck off for a few minutes and it works again. weird stuff. if anyone knows what causing it help us all out please

I had a legitmate issue on my 07 where i needed to have a bunch replaced. On my 06 it was just electronic. Disconnected the climate control center and plugged it back in, everything worked fine. I would start there then diagnose for actual problems. A lot of times these trucks are so complex all it takes is a simple "hard reset" to get things back to normal.


-- D.D.

Well got in my truck the other day and tried my ac again and it started out blowing hot air so i just shut it right off and started it right back up and it started working again, and has been working ever since. That sure was weird but am glad it started working again. Thanks for the comments.

i've had that same problem. i got an 07 classic and jus the other day was headed out of town and the ac all of a sudden turned hot. its done it a few times but all i do is turn the whole truck off for a few minutes and it works again. weird stuff. if anyone knows what causing it help us all out please

Same thing happen when I was in Dallas-- hit a small pot hole and the heater went from cold to HOT air. Stopped and turned the ignition off- and everything was OK. Happen twice, again when I hit another small hole in OK City. I am not going to worry as long as it works OK when I re-start.:cool:

Geez, sounds like there needs to be a TSB for this. I haven't had it happen yet but now I will!

My 01 does this sometimes. I dont know if its the same problem or not, but say I crank the warm air really fast to get my windows to clear on defrost, then put it back to cold, it wont go back, turn the truck off at a light, and it'll go back to cold. I thought it was that blower resistor or some stupid crap like that. idk
Brandon

Mine does the same thing with the same symtoms, out of the drivers side vents only. From research on here, it seems that it might (probably) be the drivers side blender door actuator. I just got the part (#89018365) from gmpartsdirect on Sat and havn't installed it yet, but I hope it fixes the problem.

Mine did the same thing I re-disconnected the batteries wiated 10 mins re-connected and it was fine

It's most likely the actuator. I was at the dealership the other day and spoke with a guy that had this same problem on his last two trucks. The AC would run fine one minute and blow HOT air out of one side the next. Each time he brought it in, the tech couldn't get it to screw up. Also, it would not throw any code for them to narrow it down. It screwed up again and he was near the dealership and ran it in and they checked the actuator and that was the problem.

my truck has been doing the same thing this summer. does anyone know how to replace the actuator? What about the part number? Mine is just the driver's side.

Mine does the same thing with the same symtoms, out of the drivers side vents only. From research on here, it seems that it might (probably) be the drivers side blender door actuator. I just got the part (#89018365) from gmpartsdirect on Sat and havn't installed it yet, but I hope it fixes the problem.

There is your part #

The drivers side actuator is over the passenger side of the transmission hump on the under side of the dash (HVAC unit). There are two small screws (5.5mm?) that hold it on.

:mad:I've got a 03 maxxer that does the same thing. I see the unit under the dash but there are no wires attatched to it. I found a set of wires close by but there is no way that the plug on it will plug on there. It won't hardly reach to it either, makes me wonder if there is another connection that goes on it, then to the unit. Can you tell me what color the wires going into that unit are.

Would the same part cause the problem for too cold. I was heading out of town a couple of weeks ago and had it set at 75* and you could just about hang meat in the truck. I turned it up to the highest setting, let it sit there for about 30 seconds until hot air came out, the turned back down and it was better, but still pretty damn cold.