Heating System

OPERATION
Blower
With the Ignition Switch in RUN, voltage is applied to the Heater Control. With the Heater Control in any position but OFF, voltage is applied to the Blower Motor through the Blower Motor Resistor thermal limiter and the Blower Motor runs.

Blower Motor speed depends on Blower Switch position. With the Blower Switch in LO, current must pass through all three dropping resistors and the Blower Motor runs at LO speed. With the Blower Switch in MED LO, one of the dropping resistors is bypassed and the Motor runs at MED LO speed. With the Blower Switch in MED HI, two of the dropping resistors are bypassed and the Motor runs at MED HI speed. With the Blower Switch in HI, all dropping resistors are bypassed at the Motor runs at HI speed.

Heater
The Heater Control assembly has six push-button that control various Heater functions. Five of the buttons (OFF, FLOOR, DEF/FLOOR, W. DEF, PANEL VENTS) control air flow to the floor, instrument panel and defrost outlets. The six button (R. DEF) activates the rear window defrost circuit if the vehicle is equipped with this option.

The temperature control lever moves a control cable connected to the temperature door, directing air flow through and/or around the heater core with air flow mixing downstream from the door.