Function Selector Knob
WARNING: This page is about a different car, the 1995 Ford Pickup, 1995 Ford F-Super Duty, 1995 Ford Cab & Chassis, and 1995 Ford Bronco. However, it is still accessible from the selected car via links, so may be relevant.
The function selector knob can be placed in OFF, VENT, FLOOR, MIX and DEF (defrost) positions. The position of function selector knob determines which function doors are open, partially open or closed. Function doors direct airflow to selected outlets. The 3 vacuum motors and doors are outside/recirculation, panel/defrost and floor/defrost.