One of the doors in the heater box may not be moving properly. I'm sorry, as I didnt mean that this would be the official name for this part.

The heater core simply has antifreeze moving through it, and the fan blows outside air across it, heating the air. The core doesent control where the air flows.

__________________
My first Mercedes Benz. 4/6/07.

1984 190E (201 024) 2.3L four.