My dash vent door is staying closed. The defrost and floor vents operate normally. I have the manual control and plenty of vacuum to the head unit. There also seems to be good vacuum to the door actuator that opens the air path to the vents. I can manually operate the door and it will stay open, but the next time I get in the truck and select vent, the door does not open. Are the vacuum control motors (actuators) known to go bad? I don't see a bunch of them for sale online. Thanks

01 Supercrew 4.6

 

I've yet to see one of the vacuum motors "go bad", but that doesn't mean it can't happen. Usually, the problem has been elsewhere.

Are you checking the vacuum motor with the red hose? That hose should have vacuum in any mode selection position that calls for airflow out of the panel vents and should activate the motor under that condition. When vacuum is removed, the internal spring should cause the motor to put the door back into the position for defrost.

 

Yes the actuator with the red hose. Plenty of vacuum. If I get some time at work,I'll take it out and apply vacuum to it to see if it operates.

 

Watch the actuator as you alternately attach and remove the vacuum line while its under vacuum conditions. That will tell you if the actuator works or not.