Trucks & Trailers - AC help

The AC in our 2003 Suburban will only blow out of the defrost vents. This seems like a computer problem. Is there a way to reset the computer or something? Help, it's really hot in south Alabama right now.

check your vacuum lines from the intake manifold to the firewall. Usually it's a short hose thats bad (it gets soft from age and sucks shut).

Defrost is the default setting when there is a malfunction to keep the windshield clear. If the mode setting is vacuum actuated then you need to check your vacuum supply at the fire wall where it passes through. As was already stated. If it's electronically controlled, then you would need a scan tool to check the system. You should probably just bring it into the dealer and have them look at it.

2003 model year uses electric actuators, not the old vacum actuators they used in the past. Doubt it's your computer unless you have climate control and even then, that circuit is probably not in any way related or included in your ECM. Most likely a whole seperate system from the engine. Could be the actuator, linkage came undone or even the rotary knob that controls where the air blows out. I agree with Magnus. Take it to a dealer for that kind of problem. I'm certainly no expert but I did sleep at...

And the winner is.....

Actuator.

Dealer just called. I left the part out about how this problem only started after the thing was at the dealer getting brakes and steering to the tune of 2K and 3 days. That's why I posted the query because I didn't wanna go back. Anyway, I took it back and asked them nicely to work with me on this financially given the circumstances and they did. So all is well.

I keep telling my wife it's cheaper than a new car.

Thanks guys.