I have a 2000 XC with 135000 Km on it. I was driving home last night and had the heat set at 22 degrees and the selection for the air flow set at one notchbelow defrost. When the car warmed up it was sending heat out the drivers side and the defrost ventsbut the center vent was cold air. I didn 't check the passenger side. What could be causing this? Thanks in advance

 

it could be a blend door in the air box that is not moving or not moving far enough. you could try taking it to the dealer and having the blend door reclaibrated

 

Agree, it quite possibly could be a mis adjusted blend/ air diverter door for the defroster.