AC vents put out hot air when it rains

discodan777

Hey everyone i have a chevy Tahoe 2003 the ac works great until it rains when it rains the vents put out hot air can anyone help me out and tell me how can this be fix

93tracker5spd

Hey sidcodan777, when I read your post about your AC problem I remembered something I found that sounded similar. I looked it up again; it isn't exactly like your problem but very close. This post was written on the Tahoe-Yukon Forum by twbauer. And there are a bunch of very knowledgeable people on that forum talking about these AC problems. below is a link to the posting and a copy of twbauers' answer. Just somewhere to start. Good luck!

http://www.tahoeyukonforum.com/forum/showthread.php?t=17741

FIXED!!!!!!! I can't believe it!!!

I cleaned the inside of the actuator as someone mentioned in some post I read. Ya know.. it really does make sense. If I know the motor runs when the system is calibrating, it's got to be something wrong with the "electronic sensing" of where the actuator is. It's easy to see that the goop/lubricating compound in there wouldn't allow an electrical connection on the rails, and should be cleaned up. I just used some paper towel on the end of a flat head screwdriver, and also just my finger. I also thought it may be conductive grease. I've seen that in some applications, but that wouldn't make sense either. With multiple contacts in such close proximity, electrical conductive grease would certainly short out the circuit.

Inside the actuator you'll see the motor, 3 small gears and the large gear which drives the vent shaft to change the blend doors. Under this large gear is a copper flange with 2 fingers. The 2 copper fingers ride on the bottom of the circuit board on 2 metal rails. There are sections to the rails so it's easy to see the system is looking for conductivity in the different sections to either sense or set the position of the actuator. My actuator rails and copper flange/fingers were full of gunk/grease. I cleaned them both, wiped the other gears and put the actuator back together.

Once I cleaned the actuator, set it to a mid position, I put it back in the vehicle (right above the gas pedal). I used the reset procedure that I got from the GM dealer. (pull fuse, reinstall fuse, turn key so system has power and wait for a minute or so for calibration) I pulled the HVAC 10 amp fuse in the fuse panel under the hood. Re-installed the fuse, and the stuck my head under the dash to watch the actuator while I turned the key on (1 click short of engaging the starter to get power to the climate control board and fans). I was able to see the actuator move all the way to 1 side, pause, then move all the way to the other side, pause, and then end up somewhere in the middle. Before I cleaned the actuator, I also tried this procedure, but the actuator would only go to one side, and stay there. I'm guessing there wasn't enough connection to give the climate control board any feedback on what position it was in. I waited another minute or so to ensure the sensing of the actuators was complete, and then started to play with the different fan settings and vent positions. Everything was then working as it should!!!!

I'm guessing that most people who indicate they have climate control issues after a battery going dead, or battery replacement as I did have the exact same issue. When the system re-calibrates after power loss (battery change), it moves the actuators in their full range of movement. If there is grease somewhere along that range, I'm guessing it screws up the calibration and POOF - no actuator function. The more I think about it.. the more sense it makes.

If I took this to the GM dealer, there is no way they would clean the perfectly good actuator, instead, I'd be charged a TON of labor and for a very expensive new actuator. Go Tahoe/Yukon Forum!!!

Problem Solved!!!
Last edited by twbauer; 08-25-2010 at 12:39 AM.

93tracker5spd

Hey again, sorry I misspelled your ID there.