97 Aerostar 3.0.

Factory A/C system staying on defrost.

Going to check and replace as necessary all under hood vacuum lines as soon as it cools down. I can already see some cracks in the plastic lines.
But.
Just in case, where is the actuator for the door that directs the air flow either to the dash vents or defroster vents etc?

Is it the one I can see from under the hood or in some impossible location?

 

I think it is under the metal panel where the front speakers are, requires removal of 5 difficult-to-get-to phillips screws to remove the panel, then you can see it above the glovebox area, to the left of the passenger side front speaker. With the engine running, and someone selecting the switch positions, you can see the actuator moving the linkage from outside the glass with a flashlight.

however, you might be able to get to it by removing the glovebox itself, which is easy to remove. Nearby this area there is a vacuum junction where many vacuum hoses meet.

the rapid-cool-down (MAX A/C) actuator is mounted on the right side of the blower case in the engione compartment. The symptom of a bad vacuum tube here is that the fan goes OFF when accelerating.

 

Okay, got it fixed. It was those plastic vacuum lines cracking from age and the heat of the engine. Guess Ford didn't intend for these vans to last this long.