I have a 1999 Firebird, 135,000 miles, 3800 engine. When I turn on the AC, the air comes out of the defroster vents instead of the panel vent. Moving the selector knob makes no difference. Is something wrong with the blender door, the control knob. Yesterday, the accumulator was cold with condensation on it. As I worked on the car, stopping and starting it the accumulator became warm w/no condensation. Is this another problem? I did not pull a code when I scanned it.