System Controls: Vent
WARNING: This page is about a different car, the 1994 Ford Mustang. However, it is still accessible from the selected car via links, so may be relevant.
With function selector knob in VENT position, A/C-heater air inlet duct door is closed and outside air is drawn into system and blown past evaporator core. Depending on cable-operated blend-air door setting, air then by-passes heater core and is directed past vacuum-closed heater air damper door. In VENT position, windshield defroster door is closed by vacuum to defroster outlet, and air flows through panel outlet and ducts to instrument panel registers.