When I turn on the A/C or heater it is stuck blowing out of the defroster vents. What should I expect when I take it in for repair? Is this something simple, common?

The vehicle is a 2001 F-150 Supercab. I checked the plugs to the switch, all seem snug.

 

This is the emergency default position when vacuum to the control unit and the vacuum motors is lost.

First thing, locate the vacuum line under the hood that goes through the firewall and make sure it is not disconnected or broken.

Steve