Heater, Ventilation, And Air Conditioning System Operation

NOTE: The refrigeration system on this vehicle uses R-134a which is not compatible with refrigerant R-12. Before servicing the system always make sure the proper servicing equipment is used or the system could become severely damaged. Always refer to the service text and manufacturer instructions included with the service equipment before proceeding.

The A/C system provides the following features:
^ Cooled or dehumidified air for the comfort of the occupants
^ Power ventilation
^ Windshield defrosting
^ Side window defrosting

During most operating conditions, outside air enters the vehicle in the following manners:
^ The blower motor pulls in outside air through the heater and air conditioning blower case.
^ The forward movement of the vehicle forces in outside air.

Air flows along the following path within the evaporator module:
1. Through the evaporator core
2. Through the heater core
The flow of air through the heater core is determined by the positions of the driver and/or passenger temperature valves.
3. Into the passenger compartment If the ambient temperature is above 1.7-4.4°C (35-40°F), the refrigeration system will chill the evaporator to almost freezing. This action permits operation of the air conditioning or defroster functions.

As the air passes through the evaporator, the air temperature drops. Air moisture condenses on the evaporator core tins. A gravity teed through a drain hole removes the moisture from the vehicle. This action dehumidifies the air.

From the evaporator, some or all of the air may pass through the heater core. If the system is in the heating mode, the engine coolant warms the air.

If the user selects the A/C RECIRC mode, most of the air that enters the blower motor is from the passenger compartment. The air from the passenger compartment is usually cooler than the outside air. The other modes use only outside air.