My heater works fine but it won't switch from the defrost vents position. What could be wrong with it.
Monday, December 27th, 2010 AT 7:48 PM
1 Reply
JACOBANDNICKOLAS
MECHANIC
109,702 POSTS
It sounds like you have a vacuum leak. Air flow is directed by vent doors in the HVAC system. The doors are actuated by engine vacuum. If there is a leak, the defroster is the default setting. Check under the dash for leaks. With the engine running, you may get lucky and hear a hissing sound from the leak.