1996 Bronco/F-Series

Section 12-02: Heating and Defrosting

1996 F-150, F-250, F-350, F-Super Duty and Bronco, F-Super Duty Motorhome Chassis Workshop Manual

DESCRIPTION AND OPERATION

System Airflow

The following airflow diagrams illustrate the path airflow takes in response to each functional setting of the control knob. The position of the function control knob in the heater control (18549) determines which of the damper doors are open, partially open, or closed.

OFF

In the OFF position, the OUTSIDE AIR door is closed to block the entry of air from the cowl into the heater air plenum chamber (18471).

VENT

NOTE: The temperature door can be set to full cool, full warm or anywhere in between. The function control knob does not affect the temperature blend door; this is governed by the temperature control knob.

In the VENT position, the OUTSIDE AIR door is open and the PANEL/DEFROST door is open. The airflow is directed to the registers in the instrument panel (04320).

FLOOR

In the FLOOR position, the OUTSIDE AIR door is open. Airflow is directed through the TEMPERATURE BLEND door opening, through the heater core (18476), past the closed FLOOR/PANEL door and out through the open FLOOR/DEFROST door to the heater outlet floor duct (18C433). There is also an air bleed past the closed FLOOR/DEFROST door to the windshield defroster openings.

MIX

In the MIX position, the airflow follows the same path as described for FLOOR position, except the FLOOR/DEFROST door is in the mid-position with an equal amount of air flowing to the heater outlet floor duct and the windshield defroster nozzle.

DEFROST

In the DEFROST position, the FLOOR/DEFROST door is fully open to the windshield defroster hose nozzle (18490) with a bleed amount going past the closed door to the heater outlet floor duct.

Airflow Diagrams