2004 Yukon A/C blowing HOT air!

[samwaite]

I have a 2004 Yukon SLT. It has three AC/Heat zones - left front, right front and rear. The left front and rear zones frequently start blowing heated air. Most of the time, they correct themselves and resume cooling, but have recently started blowing 120 degree hot air at full fan force, as if I had turned the thermostat all the way up. I have to pull over, turn off the car, sit for a few seconds, then restart, and that seems to reset the system and it works properly. The front right zone doesn't seem to be affected. Sometimes the rear zone only starts heating.

 

Any ideas?

[SILVERADOSC540]

check in with chawkins6789

Got the call from the dealer, both air temp actuators were bad so $1350 but on top of that another $340 because the control head is bad too

 

not sure if you're having the same issue, but same year and sounds similar...

[jwhjr]

Blend door actuator is my guess, not sure how many there are on a truck with rear air though.

[samwaite]

UPDATE - Well, I there appear to be 3 actuators on this application. One is located on the bottom of the heater box, and controls the left/right front temp. One is located on the driver's side end of the box and controls air flow to the windsheild/front dash vents. The third one one is on top of the box, and I'm not sure whether it controls the back air or not yet. But, I replaced the one on the bottom (cost $138) and it appears to have corrected the driver's side hot/cold issue. I'm going to test that last actuator (the one on the top of the box) and see if it controls the back air by feeling for movement when I move the temp control to hot then cold. This system is quite an interesting piece of engineering, but I think I'm starting to figure it out. Maybe Once I figure it out, I'll post part numbers for everyone to use. This isn't real hard to do, once you determine which to change, just need to get your fingers in some tight spaces.

[ACannell]

Any further update? Mine is doing something quite similar now and I'm just starti ng to look into it. Thanks for the posts Sam.

[maddog65]

Today I had a similar problem. I have an 07 Yukon Denali with a digital control. I was getting hot air on the driver side and cold air on the passenger side. Both were set to a cold temp and A/C was selected as well.

The odd thing about this is I saw this post a few weeks ago and was thankful I did not have this type of problem.

Go figure.

Any update would be greatly appreciated

Jay