Air Conditioning
Air Conditioning
The refrigerant system components include the following:
- A/C compressor and clutch assembly
- A/C condenser core
- A/C evaporator core
- Suction accumulator
- Connecting refrigerant lines
- Evaporator core orifice
The refrigerant system incorporates an A/C compressor controlled by the PCM through an A/C clutch relay. An A/C cycling switch is used to cycle the A/C compressor off when the pressure in the low-pressure side of the refrigerant system falls below an acceptable level.
An A/C compressor pressure relief valve is installed in the A/C compressor to protect the refrigerant system against excessively high refrigerant pressures.
A/C Compressor and Clutch Assembly
NOTE: Internal A/C compressor components are not serviced separately. The A/C compressor is serviced only as an assembly. A new A/C pressure relief is included with replacement A/C compressors, but the valve is also available as a separate component and can be independently replaced if needed. The A/C compressor clutch, A/C compressor pulley and A/C clutch field coil are included with replacement A/C compressors, but are also available as a separate assembly and can be independently replaced if needed.
The A/C compressor has the following characteristics:
- A non-serviceable shaft seal.
- The A/C compressor uses PAG Refrigerant Compressor Oil (R-134a Systems) YN-12-D. This oil contains special additives required for the A/C compressor.
- The A/C compressor oil in the A/C system may darken over time while maintaining normal oil viscosity. This is normal for A/C systems because of break-in wear.
- Use the refrigerant oil adding procedure specified for this vehicle when installing a new A/C compressor or any other A/C component. Refer to the Refrigerant Oil Adding procedure in Heating and Air Conditioning.
When battery voltage is applied to the A/C compressor clutch field coil, the clutch disc and hub assembly is drawn toward the A/C clutch pulley. The magnetic force locks the clutch plate and hub assembly and the A/C clutch pulley together as one unit, causing the compressor shaft to rotate with the engine. When battery voltage is removed from the A/C compressor clutch field coil, springs in the clutch plate and hub assembly move the clutch plate away from the A/C clutch pulley.
A/C Pressure Relief Valve
NOTE: If the A/C compressor is operating within limits and the A/C pressure relief valve is venting, or if the A/C pressure relief valve is leaking around the threads, install a new A/C pressure relief valve and O-ring. If the new A/C pressure relief valve still vents after it is installed, diagnose the refrigerant system for a restriction.
An A/C pressure relief valve is incorporated in the A/C compressor to prevent damage to the A/C compressor and other system components by relieving unusually high system discharge pressure buildups. For specifications regarding operating pressure(s), refer to Heating and Air Conditioning.
The A/C pressure relief valve is a separate component and can be installed separately from the A/C compressor. It is necessary to recover the refrigerant before removing the A/C pressure relief valve.
A/C Condenser Core
The A/C condenser is an aluminum fin-and-tube design heat exchanger located in front of the vehicle radiator. It cools compressed refrigerant gas by allowing air to pass over fins and tubes to extract heat, and condenses gas to liquid refrigerant as it is cooled.
A/C Evaporator Core
NOTE: The evaporator core is not separately serviceable, it is serviced only with the evaporator core housing assembly.
The evaporator core is an aluminum plate/fin type and is located in the heater core and evaporator core housing. A mixture of liquid refrigerant and oil enters the bottom of the evaporator core through the evaporator core inlet tube and continues out of the evaporator core through the evaporator core outlet tube as a vapor. During A/C compressor operation, airflow from the blower motor is cooled and dehumidified as it flows through the evaporator core fins.
Evaporator Core Orifice
The evaporator core orifice is located in the condenser-to-evaporator line and can be removed and installed through an access fitting. The evaporator core orifice provides a restriction to the flow of refrigerant from the high-pressure side of the refrigerant system, and separates the low-pressure and high-pressure sides of the refrigerant system.
Suction Accumulator
NOTE: Installation of a new suction accumulator is not required when repairing the A/C system, except when there is physical evidence of contamination from a failed A/C compressor or damage to the suction accumulator. Damage to the suction accumulator includes leaks in the suction accumulator, physical damage to the suction accumulator shell or desiccant, or moisture contamination. Moisture contamination results only from a complete loss of refrigerant, and equalization of the refrigerant system pressure with atmospheric pressure for a period longer than 1 hour. If even a slight amount of position refrigerant pressure is present in the refrigerant system before repairs are carried out, the suction accumulator should not be replaced.
The suction accumulator is used to prevent residual liquid refrigerant from reaching the A/C compressor after leaving the evaporator core. The suction accumulator allows the accumulated heavier liquid refrigerant and oil mixture to re-enter the compressor suction line at a controlled rate. A desiccant bag is mounted inside the canister to absorb any moisture which may be in the refrigerant system.
The suction accumulator is located behind the RH front corner of the front bumper cover in front of the RH fender splash shield.
A/C Cycling Switch
The A/C cycling switch is used to prevent icing of the evaporator core by cycling OFF the A/C compressor clutch when the suction pressure in the low-pressure side of the refrigerant system drops below acceptable levels. The PCM monitors the A/C cycling switch. When the A/C cycling switch contacts are open, the PCM will disengage the A/C compressor clutch.
The A/C cycling switch is located on a Schrader-type valve fitting on the evaporator outlet line. It is not necessary to recover the refrigerant to remove the A/C cycling switch.
A/C Pressure Transducer
The A/C pressure transducer monitors the compressor discharge pressure and communicates with the PCM. The PCM will interrupt A/C compressor operation in the event that the A/C pressure transducer indicates high system discharge pressures. It is also used to sense low charge conditions. If the pressure is below a predetermined value for a given ambient temperature, the PCM will not allow the clutch to engage.
The A/C pressure transducer is located on the condenser-to-evaporator line behind the RH corner of the front bumper cover. It is not necessary to recover the refrigerant before removing the A/C pressure transducer.
Service Gauge Port Valves
The high-pressure service gauge port valve is located on a vertical extension off the compressor-to-condenser discharge line behind the RH headlamp.
The low-pressure service gauge port valve is located on the suction accumulator behind the RH corner of the front bumper cover, and can be accessed by detaching the front portion of the RH fender splash shield.
The fitting is an integral part of the refrigerant system line or component.
- Special couplings are required for both the high-side and low-side service gauge ports.
- A very small amount of leakage will always be detectable around the Schrader-type valve with the service gauge port valve cap removed, and is considered normal. A new Schrader-type valve core can be installed if the seal leaks excessively.
- The service gauge port valve caps each include an O-ring seal which is used as a primary seal in the refrigerant system to prevent leakage through the Schrader-type valves from reaching the atmosphere. The service gauge port valve cap O-ring seals should be checked when checking the refrigerant system for leaks and a new cap should be installed if needed. Always install and tighten the A/C service gauge port valve caps to the correct torque after they are removed.
Refrigerant System Dye
Fluorescent refrigerant system dye is added to the refrigerant system at the factory to assist in refrigerant system leak diagnosis using a Rotunda-approved ultraviolet black light. It is not necessary to add additional dye to the refrigerant system before diagnosing leaks, even if a significant amount of refrigerant has been removed from the system. Replacement suction accumulators are shipped with a fluorescent dye "wafer" included in the desiccant bag, which will dissolve after approximately 30 minutes of continued A/C operation. It is not necessary to add dye after flushing or filtering the refrigerant system because a new suction accumulator is installed as part of the flushing or filtering procedure. Additional refrigerant system dye should only be added if more than 50% of the refrigerant system lubricant capacity has been lost due to a fitting separation or hose rupture. Refer to Heating and Air Conditioning.