Hi
Demister in my volvo s70 is blowing cold through the middle vents even when heating is set on full. Vents located by driver and passenger door are blowing hot as they should.
My volvo has dual temp control.
Does anyone know about this problem? Many thanks

 

likely something is up with the blend doors that control airflow from the heater core and the AC evaporator to the vents. I believe the S70s have 5 motors that actuate the blend doors which can either fail, get out of sync or have the actuator rods fall off or bind.

Do you have any indicator lights on the AC or REC buttons to suggest the climate control ECU has presented a fault code? (these codes can be scanned by an advanced OBD2 scanner)