Ac on the driver side blows hot air

[Portus]

The ac works well but after a little while the ac on the driver side starts blowing hot air. It's a 2004 GMC Sierra. Any help would be much appreciated.

[jake111]

My understanding from discussions years ago was that the blend door actuator(s?) (or the computer controlling it/them) gets confused because of, probably, "position out of range". An experienced programmer would have handled this, but I don't think GM used one, so it goes into a "safe" mode . . . full-on heat so you don't freeze to death.

 

Sometimes you can just shut off the climate control, wait maybe 30 seconds, and turn it back on and all is good (mine usually cleared doing this although it hasn't screwed up for a couple of years now).

 

Sometimes you can just shut off the truck, wait maybe 30 seconds, and turn it back on.

 

Sometimes you have to pull the a/c or climate control fuse (there are youtube videos), wait a minute (maybe turn on the key and then turn it off, but not sure this is needed, then turn off the key), then put the fuse back in.

 

In all 3 methods above DON'T touch any climate control buttons for several minutes. In some cases (or maybe only the last one above) the actuators are re-calibrating; changing the controls messes it up.

 

Or, an actuator door has gone bad and needs to be replaced. I haven't done this but understand it might be a difficult job because the actuators are buried.

[Formulabruce]

Blend door motor gear has jumped, you may hear a click as it tries to get to its correct position.

[4bycamper]

To fix that hot AC problem, we ordered a blend door motor from ebay. Installed it in less than 1 hour.

 

There is a bath tub shaped heat/noise baffle under the dash. Comes out with 3 bolts. Blend motor is to the right of the gas petal.