Function Selector Knob

WARNING: This page is about a different car, the 1995 Ford Aerostar. However, it is still accessible from the selected car via links, so may be relevant.

Function selector knob on main heater control panel assembly controls air distribution for main and auxiliary units. See Figure. The auxiliary unit operates in FLR mode when function selector knob is in FLR, MIX or defrost position.

If function selector knob is in VENT position, a vacuum-operated valve interrupts hot coolant flow to auxiliary unit. The unit recirculates interior air through side and overhead ducts.