Chevrolet Repair: 1999 Prizm, defrosters, prizm

Question
I just had extensive Air Conditioning repair and now my wife was driving the car and put the defrosters on and now it is stuck there, I can turn the knob all I want and it will not move from the defrost vents, get a little cold air out of the middle vents.

Answer
HI JIM,I DONT KNOW WHAT KIND OF A/C WORK YOU HAD DONE,IF IT IS WAS THE EAVAPORTOR,THIS IS UNDER THE DASH. IT SOUNDS LIKE THEY DAMAGED THE BLEND DOOR OR HOOKED THE BLEND DOOR LINKAGE UP INCORRECT. IF THE WORK WAS NOT DONE UNDER THE DASH THEN THIS IS A NEW PROBLEM...THIS MAYBE UNDER WARRANTY IF THEY DID REPALCE THE EVAPORATOR..HOPE THIS HELPS YOU..