No heat or air thru vents ... help?

[niemoj]

Hi-

I can't figure this one out. When I switch the air or heat on, the air only goes thru the defroster vent. When I twist the knob, on the panel, to adjust where I want the the heat to come out, it doesn't switch. Is there a relay fuse or something I need to replace or, do I need to replace the switch panel. Please advise.

Thanks

[Lupin1x]

I had the same problem with an F-150. The problem was that Ford hadn't opened up the vent shaft to let air travel anywhere else but through the defrost. If it's a newer truck this is most likely your problem. If the truck is older and it had worked before, than it's likely you broke a cable behind the heat control system, this might not be so easy to fix.

[Farm_Boy]

If it only blows out the defroster vent, and it blew out the correct places before, then it should be like Lupin1x said, either a cable that controls the damper in the heater box located behind the glove compartment or on newer trucks it could be a vaccum or electric controler that operates the damper. The damper moves and directs the air through different vents (like a door). You have to find out if it is operated by a cable, vaccum or electric. Good luck.