HVAC Control Systems: Heaters: PONTIAC: Description: Notes

NOTE: Vacuum and wiring diagrams are at end of article.

Air enters the heater system through an opening at the rear of the hood, passes through the plenum chamber into the blower motor, and then into the air inlet duct. When heated air is desired, the blower forces air taken from the blower and air inlet across the heater core and through on air distribution system to air outlets inside the passenger compartment.

Airflow control doors are moved by bowden cables. All models utilize three doors: a temperature door, an air door, and a defroster door.

Depending on the setting of the control levers on the control panel, heated air is either distributed in the passenger compartment by a center outlet under the heater duct, or is directed through a different duct to the defroster nozzle and the windshield.