Air Conditioning
AIR CONDITIONINGThe main A/C refrigerant system is a clutch cycling orifice tube type and the auxiliary A/C refrigerant system is a thermostatic expansion valve (TXV) system. The system components are the following:
- A/C compressor
- A/C condenser core
- A/C evaporator core
- Suction accumulator
- Connecting refrigerant lines
The refrigeration system operation is controlled by the:
- evaporator core orifice tube.
- A/C cycling switch.
- A/C pressure transducer.
- thermostatic expansion valve.
The refrigerant system incorporates an A/C compressor controlled by the powertrain control module (PCM) through an A/C clutch relay.
The A/C cycling switch senses evaporator core pressure to control A/C compressor operation.
An evaporator core orifice tube is installed in the condenser to evaporator line to meter the liquid refrigerant into the evaporator core.
The A/C compressor clutch will only be engaged by the PCM if all of the following conditions are met:
- The climate control assembly is set to a mode which provides an A/C request to the PCM.
- The A/C cycling switch is not open due to a lower than acceptable pressure on the low pressure side of the refrigerant system.
- The A/C pressure transducer is reading an acceptable pressure in the high side of the refrigerant system.
- The A/C compressor relay is switched to the closed position by the PCM.
- The engine coolant temperature is not excessively high.
- The PCM has not detected a wide open throttle (WOT) condition.
An A/C compressor pressure relief valve is installed in the compressor manifold and tube assembly to protect the refrigerant system against excessively high refrigerant pressures.