i have a 99 3.8 and my upper vents dont work. i have air at the floor board. i changed the switch and the vacuum line leading out to the hood but dont know where to look next.

 

The air is directed to different places my moving the air doors inside the HVAC plenum. The motion of the air doors is controlled by vacuum powered actuators/motors.


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[&:] the doors are controlled by vacuum and more than once ive found the vacuum supply lines or the tee/one way valve at the firewall to have broken. id check this stuff first kurt

 

Do you have defrost? Ifyes thenyou couldsuspect no vacuum. Defrost is a default so you will always have if for safety. If no defrost then maybe some thing could have also fallen in through the vents and jambed a door.