climate control knob???????

I have a 1994 Corsica, and the button you turn to adjust to heat, defrost,vent..etc..is not working. It turns, but no matter which one I turn it to..it only comes out the vents. What is the problem, and how do I fix it? My thinking is that it is supposed to open like a flap thing that moves and directs the air to different places, i.e.the floor, windshield. I have 2 Chilton books on this car and not a mention of this.Please help!! Lindsey

It could be a broken vacuum hose... do you hear a hissing noise inside the car, by where the climate control is located?
It might be mis-alligned, try shifting thru the settings really slow with the engine off and hear if you feel a diff in the air pressure and air dam flaps