2007 GMC heater AC?

Compressor is working. Suction line is very cold.

Fan speeds work. Control on right work. Puts air where you want it.

Only heats cones out the vent you select.
Talk to me about the dual temp controls work.

I'm thinking there is a motor that works on manifold vacuum some place.

What do the experts say?

George

Stuck Blend door, or blend door motor. Google it. Jim

No vacuum motors are used, it's all electric.

The sliders control 2 actuator motors/servos that operate a split blend door which can break or jam from debris such as pens dropping down the defrost vents.

Since neither side works there must be a common failure point between them, just one failed actuator wouldn't cause BOTH to stop working.

I've got a 2004 GMC which should have the same set-up. There are two blend door actuators which open or close to blend the hot air from the heater with the cold air from the AC. One is located over the center hump and is relatively accessible even for a fat old man like me. The second is located where it can be seen be removing the glove box. There are a lot of YouTube videos covering the replacement. One example is :

https://www.youtube.com/watch?v=8kUK8sZD59Q

My 2004 GMC is a basic work truck model, and for some unknown reason used a different part number for the over-the-hump actuator than I found in the look-up catalog. After the first one I purchased would not fit, I took the old one back to a Napa store. By looking at the pictures in a catalog, I found the same one, and the description said that it fit a 2004 GMC. (a search for parts for a 2004 GMC did NOT list this part number.)

A couple of years later the other actuator started acting up. With my fat hands, the only way to change it would be to remove the entire dash board to gain access, and that looked like a full day job with lots of swearing and bleeding. I found a couple of other articles on the net that suggested pulling the appropriate fuse or disconnecting the battery for a few minutes to see if the computer would reset itself in some unknown manner. I tried this, and the actuator started working again. It has worked for two or three years, but the truck is one I uses as an emergency back-up at my Sullivan County rural place. I doubt that I have put 100 miles on the truck in the past three years.

Tom,
Thanks. I didn't know what to call vacuum motors. Actuators.
My truck is also a work truck

George

I figured that out. I unplugged it. Started up the truck and cold AC. Might be a different story once engine comes up to full temperature. Thanks YOU ALLS.
George

Tom,
Many thanks. I need to replace driver's side actuator. Passenger's side is good. I would dread replacing passenger's actuator.
It's about time everything starts failing. Can't buy new truck. Lots are empty. Plus I would have to special order the work truck I want.
So I'll just have to repair the old girl.

George

The passenger side of our Acadia went full cold during a winter trip to Florida. My wife had to bundle up in a blanket for half the trip. It was a little over $500 to get it fixed at the dealer; something like $125 for the motor and the rest was labor.

Check it out on You tube. The passengers side is a witch to replace. Glad mine driver's side. I would have pulled the power wire to AC compressor.