Air Conditioning System

The compressor, driven by the vehicle engine, compresses gaseous refrigerant to high pressure, and the refrigerant temperature rises significantly. The compressed and heated refrigerant is then supplied to the condenser mounted on the cooling system radiator. The condenser cools the gaseous refrigerant, which turns into liquid. The liquid refrigerant flows into the receiver/drier, where moisture is removed from it, and then supplies the liquid to the evaporator located in the heater unit inside the vehicle cabin. In the evaporator, the liquid refrigerant evaporates, changing to a gaseous state, and lowers the temperature of the air entering the cabin. The gaseous refrigerant then returns to the compressor and the cycle repeats.

The A/C relay controls the electrical circuits of the condenser fan and the A/C compressor. The relay is controlled by the engine control module. If the coolant temperature exceeds a specified value, the engine control module turns off the relay, which turns off the air conditioning system. When the engine is started or the vehicle accelerates, the engine control module turns off the relay, which turns off the air conditioning system for 5 seconds.

The blower fan draws air through the evaporator core, which increases the flow of cooled air supplied to the passenger compartment. The blower fan speed is determined by the blower switch position and the blower resistor unit.

The A/C compressor is the primary component of the air conditioning system. If the A/C compressor fails, the refrigerant is not compressed and circulated through the air conditioning system circuit. The A/C compressor is driven by a belt from the crankshaft pulley.

The A/C compressor clutch engages the compressor. The clutch is electromagnetically controlled.

The condenser is installed in front of the radiator. The condenser fan increases the airflow through the condenser.

The blower/evaporator unit contains the blower motor, the A/C relay, the evaporator core, and the expansion valve.

The evaporator core cools and dehumidifies the air. As the air is cooled, moisture from the air condenses on the evaporator, and cool, dry air enters the passenger compartment.

The expansion valve allows liquid refrigerant under high pressure to expand as it enters the evaporator. The valve meters the amount of liquid refrigerant to prevent flooding of the evaporator.

The dehumidified air can be reheated as it passes through the heater core. The heater core is heated by the hot coolant flowing through it.

Liquid refrigerant from the condenser enters the receiver/drier, where moisture is removed, and then the refrigerant flows to the evaporator.
The air conditioning system is charged with R-134a refrigerant.

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