Toyota Repair: Air Conditioner Control, toyota camry, center vents

Question
I have a 94 Toyota Camry.  The AC works but does not blow through the center vents.  It blows out through the defroster vents.  When control knob is turned it sounds like it tries to change over and I hear a flap like sound then it goes back to full blast through the defroster.

Any ideas?

Answer
There is a problem with the vent control, possibly the control cable has come off at the lever for the air door under the dash or the cable came off at the in dash control, if you have difficulty moving the control knob the problem is in the dash control, if the knob moves freely check the cable connection under the right side of the dash this is where the cable connects to direct the air flow, move the knob while looking for the cable that moves.