Mercedes Benz repair: 1992 190E 2.6L A/C blend door issue, climate control unit, vacuum motor

Question
I have a 92 mercedes benz 190E, its a 2.6L and the problem is with the a/c. Any time i have the a/c it blows hot air out the top. But when i turn the air off it doesn't blow hot. So anytime there is ac coming out the front of the car it also has hot air coming out the top. The cold is cold and hot is hot. Im not sure what the problem is. thanks

Answer
Best guess:
This is a blend door issue, typically (on older models) caused by broken vacuum motor diaphragms or hoses.

Climate Control:
http://www.mercedesshop.com/shopforum/showthread.php?t=142408

Your system may need a new Climate Control Unit.
http://catalog.eautopartscatalog.com/mercedesshop/sophio/wizard.jsp?partner=merc...