I can hear the heater working but nothing comes out when set to "vent" or when the AC utilizes the "vent control". On all other settings the heater works fine. Is there a seperate fan for the vent heat? If so is there a seperate fuse for it? Are these fans knows to break? Any advise will be usefull. Thanks, Tyler

 

See if it's blowing out the defrost when that happens, if so, your vacuum cannister is leaking, or the vacuum line or check valve to the cannister is bad. I think.