Heating and Air Conditioning: Description and Operation

Heater System:

Switch Functions:

Mode Selector Switch and Air Flow:

System Control Flow:

Heater System
The heater control unit is located in the middle portion of the instrument panel.

The heater unit has mode doors and an air mix door. The intake unit has an intake door and a blower motor. The heater unit and the intake unit are regulated by their control units.

Fresh outside air is introduced into the cabin through the center and side ventilators when the blower fan is operated.

All models are equipped with front side window defrosters. An optional filter is provided in front of the evaporator inlet.

Air Distribution Ratio:

The diagram shows air distribution for each position of the mode selector dial.

Air Conditioning Cycle:

Air Conditioning Cycle
The refrigerant recirculates in the air conditioning system, flowing out of the compressor, passing through the condenser, receiver drier and evaporator, and returning to the compressor.

The flow of refrigerant to the evaporator is controlled by an expansion valve located inside the evaporator.

The compressor operates and stops repeatedly to maintain the evaporator temperature within a specified range. When the evaporator temperature falls below the specified temperature, the thermo-control amplifier stops the compressor operation. When the evaporator temperature rises above the specified temperature, the thermo-control amplifier puts back the compressor into operation.

The refrigerant system is protected against excessively high or low pressures by a pressure switch. If the system pressure rises or drops excessively, the pressure switch is activated to prevent the compressor from operating.