Air Vent Controller...No Defrost

I have a '95 that the controller for the air vents doesn't work. It blows out of the floor but no matter where I set the selector it will not move. So, I have no defrost or other vents. The fan control works fine...it's just the vents.

Any ideas on what needs to be replaced? Someone told me that it is the entire controller behind the dash that needs to be replaced?

The actuator arm probably fell off the duct box under the dash. It goes right back on if this is what happened

I had the same problem, couldn't change which holes the air blew out of. Maybe it is just some loose connecting rod, but I had to replace the whole control unit (about $150 I think). As a temporary solution to get the defroster to work, I disconnected the actuator arm and moved it to the upper position. I'm no mechanic, but I seem to remember that the controller sends different voltages for different positions of the ductwork. Not just voltage or not, but different ones for floor, middle, upper and combinations. Good Luck.

I have a similar problem with my 99 Suburban. When cold you can change location for air to blow out. Once operating temperature is reached you can not change the location where the air blows out. This occurs whether heating or cooling.