AC Actuators and Antenna Plug

How the A/C actuators work: they’re used only in the “COLD IA” (cold inside air / recirc) position, just left of COLD. Two parallel vacuum pots: one closes the cowl-plenum flapper (shutting off outside air), the other opens the passenger kick-panel vent to draw inside air into the evaporator. “COLD OA” (just right of COLD) switches the vacuum off so the springs return them for outside air. Mid-way toward HOT the compressor switches off and intake air mixes through the heater core; full HOT runs all air through the heater core. VENT opens the plenum and closes the recirc with the compressor off and heater bypassed.

The kick-panel flapper replaces the manual one on non-A/C cars (a domed color-matched cover protects it). Without the actuators you lose the MAX-AC/RECIRC function — likely fine in cooler climates.