Mercedes: Mercedes 190E Climate Control, climate control unit, climate control system

Question
My 1993 Mercedes 190E 2.3L climate control system seems to have problems and is stuck. If the fan is on, the side and windshield vents always blow HOT air and the center dash vents blows cold if the AC is on. Nothing ever comes from below the dashand the direction controls seem totally inoperative as to me deciding which vents the air should blow from. This occured one time before on a rainy day but quit after the car was shut off and restarted. Now it is all the time. Any help would be greatly appreciated.
Thanks

Answer
Best guess:
#1. Bad climate control unit.
#2. Vacuum pods bad.

Climate Control Unit
http://catalog.eautopartscatalog.com/mercedesshop/sophio/wizard.jsp?partner=merc...