System Airflow

AIR INLET
The system pulls outside (ambient) air through the cowl opening at the base of the windshield. Then it goes into the plenum chamber above the heater-A/C unit housing. On air conditioned vehicles, the air passes through the evaporator. At this point the air flow can be directed either through or around the heater core. This is done by adjusting the blend air door with the TEMP control on the control head.
ZONE CONTROL
An optional zone control Heating Ventilation and Air Conditioning (HVAC) control module is available. This unit has dual blend-air doors that can be regulated independently of each other. The temperature setting can be different from driver's side to passenger side.
AIR OUTLET
After the air passes the blend-air door(s), the air flow can then be directed from the Panel, Floor, and Defrost outlets. Air flow velocity can be adjusted with the blower speed selector switch on the control head.
AIR RECIRCULATION
Ambient air intake can be shut off by closing the recirculating air door. This will recirculate the air that is already inside the vehicle. This is done by depressing the Recirc. button on the control head.
DEFROST OR MIX MODES
On air conditioned vehicles, moving the control to Mix or Defrost depresses the A/C button and will engage the compressor. This will send refrigerant through the evaporator, and remove heat and humidity from the air before it goes through the heater core.

CAUTION: In cold weather, use of the Recirculation mode may lead to excessive window fogging. The Recirculation mode is automatically deactivated in Mix and Defrost modes to improve window clearing operation.