The air conditioner relay controls the electrical circuits of the condenser fan and the air conditioner compressor. The relay is controlled by the engine control unit. If the coolant exceeds a certain temperature, the engine control unit turns off the relay, which turns off the air conditioning system. When the engine is started or the vehicle accelerates, the engine control unit turns off the relay, which turns off the air conditioning system for 5 seconds.
The fan blows air through the evaporator core, increasing the flow of cooled air into the vehicle. The fan speed is determined by the position of the fan switch and the resistor pack.
The air conditioning compressor is the primary element of the air conditioning system. If the air conditioning compressor fails, there is no compression and movement of the refrigerant through the air conditioning system circuit. The air conditioning compressor is driven by a belt from the crankshaft pulley.
The air conditioning compressor clutch engages the compressor. The clutch is electromagnetically controlled.
The condenser is mounted in front of the radiator. The condenser fan increases the air flow through the condenser.
The fan/evaporator assembly contains the fan motor, air conditioner relay, evaporator core and expansion valve.
The evaporator core performs the functions of cooling and drying the air. When the air is cooled, moisture from the air is deposited on the evaporator and cooled dry air enters the car interior.
The expansion valve allows the high-pressure liquid refrigerant to expand as it enters the evaporator. The valve allows a certain amount of liquid refrigerant to pass through to prevent flooding of the evaporator.
The dried air can be reheated by passing through the heater core. The heater core is heated by the hot coolant passing through it.
The receiver/dryer receives liquid refrigerant from the condenser, where water is removed from it and then the refrigerant flows to the evaporator.
The air conditioning system is filled with R-134a refrigerant.