1996 Grand Prix Heater Controls

This vehicle took a significant front-end collision last summer. Repairs were done by a competent mechanic and I am satisfied that they were done well. Since the accident, however, the HVAC system directs all air out the defroster vents, no matter what position the control switch is in. The fan works fine and, although I think it needs a freon charge because it blows hot when the temp is set to "hot" but blows at about ambient temp when it is set for "cold, I think the AC compressor is okay." Does the vent control switch operate servos that open different ducts for the various vents? I'm hoping that I can simply replace a switch and get a charge to get my daughter some AC.

Thanks