Air Conditioning
AIR CONDITIONINGThe A/C refrigerant system is a clutch cycling, thermostatic expansion valve type. The system components are:
- A/C compressor
- A/C clutch
- A/C condenser core
- A/C evaporator core
- Thermostatic expansion valve (TXV)
- Receiver/drier
- Connecting refrigerant lines
The refrigeration system operation is controlled by the:
- TXV.
- evaporator discharge temperature sensor.
- A/C compressor pressure relief valve.
- A/C pressure transducer.
- powertrain control module (PCM).
- dual-zone EATC module.
- ambient temperature sensor.
The refrigerant system incorporates a variable capacity A/C compressor. The A/C compressor clutch engagement is controlled by the vehicle PCM.
The evaporator discharge temperature sensor senses evaporator discharge temperature. The dual-zone EATC module monitors the evaporator discharge temperature sensor and communicates with the PCM to control clutch cycling. The dual-zone EATC also monitors the ambient air temperature sensor and disables A/C operation when the ambient air temperature is below 0°C (32°F).
The A/C pressure transducer is located in the compressor discharge line and is monitored by the PCM. If high or low refrigerant pressures are experienced, the PCM will interrupt A/C compressor operation.
The pressure relief valve is installed in the compressor manifold and tube assembly and protects the system from excessively high refrigerant pressure.
The TXV, which is mounted to the evaporator core inlet and outlet tubes, contains an adjustable orifice which provides the restriction that separates the high and low-pressure liquid phases in the refrigeration system.
A/C Compressor and Clutch Assembly
NOTE: Internal A/C compressor components are not serviced separately. The variable scroll compressor is serviced only as an assembly. The A/C clutch, A/C clutch pulley and the A/C clutch field coil are serviceable.
The SC105V Variable Scroll A/C compressor has the following characteristics:
- A variable capacity function controlled by a suction pressure sensing device.
- A fixed and orbiting scroll to provide refrigerant compression.
- A non-serviceable shaft seal.
- The A/C compressor uses PAG Refrigerant Compressor Oil (R-134a Systems) F7AZ-19589-DA (Motorcraft YN-12-C) or equivalent meeting Ford specification WSH-M1C231-B. This oil contains special additives necessary for the A/C compressor.
The A/C compressor contains a thermal cutout switch which senses the compressor housing temperature. The switch will disengage the A/C compressor clutch if the housing temperature exceeds 120°C (247°F).
The SC105V magnetic A/C clutch has the following characteristics:
- It drives the compressor shaft.
- When battery positive voltage (B+) is applied to the A/C clutch field coil, the clutch disc and hub assembly is drawn toward the A/C clutch pulley.
- The magnetic force locks the clutch disc and hub assembly and the A/C clutch pulley together as one unit, causing the compressor shaft to rotate.
- When B+ is removed from the A/C clutch field coil, springs in the clutch disc and hub assembly move the clutch disc away from the A/C clutch pulley.
A/C Compressor Pressure Relief Valve
An A/C compressor pressure relief valve is incorporated into the compressor A/C manifold and tube to:
- relieve unusually high refrigerant system discharge pressure buildups. For specifications regarding operating pressure(s), refer to Specifications.
- prevent damage to the A/C compressor and other system components.
- avoid total refrigerant loss by closing after the excessive pressure has been relieved.
A/C Condenser Core
The A/C condenser core has the following characteristics:
- It 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 by condensing gas to liquid refrigerant as it is cooled.
Refrigerant Lines
The manifold and tube assembly - receiver/drier carries the high-pressure liquid from the condenser core to the receiver/drier, and from the receiver/drier to the manifold and tube assembly - thermostatic expansion valve (TXV). It attaches to the A/C receiver drier, uses O-ring seals, and also contains the high-pressure service port.
The manifold and tube assembly - thermostatic expansion valve carries high-pressure liquid to the thermostatic expansion valve and low-pressure gas from the thermostatic expansion valve to the manifold and tube assembly - A/C compressor.
The manifold and tube assembly - A/C compressor carries the high-pressure gas from the A/C compressor to the condenser core. It also carries the low-pressure gas received from the manifold and tube assembly - thermostatic expansion valve to the A/C compressor. The A/C manifold and tube assembly is attached to the A/C compressor, uses O-ring seals, and has:
- a Schrader-type valve stem core fitting used to mount the A/C pressure transducer so that the A/C pressure transducer can be removed without discharging the A/C system.
- a serviceable high-pressure relief valve.
A/C Evaporator Core
The A/C evaporator core is the plate/fin type.
- A mixture of refrigerant and oil exits the TXV and enters the evaporator tank area through the 12.7-mm (1/2-in) tube.
- It exits the evaporator through the15.9-mm (5/8-in) tube then passes through the TXV.
A/C Thermostatic Expansion Valve
A/C Thermostatic Expansion Valve:
The TXV is located between the evaporator core lines and the thermostatic expansion valve manifold and tube assembly at the rear of the engine compartment. The TXV 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. Refrigerant entering and exiting the evaporator core passes through the TXV through 2 separate flow paths. An internal temperature sensing bulb senses the temperature of the refrigerant flowing out of the evaporator core and adjusts an internal pin-type valve to meter the refrigerant flow into the evaporator core. The internal pin-type valve decreases the amount of refrigerant entering the evaporator core at lower temperatures, and increases the amount of refrigerant entering the evaporator core at higher temperatures.
Receiver/Drier
The receiver/drier is mounted to the engine fan shroud to the right of the vehicle center. The inlet tube of the receiver/drier attaches directly to the A/C condenser core and the outlet tube of the receiver/drier attaches to the thermostatic expansion valve inlet line.
The receiver/drier stores high-pressure liquid after it leaves the condenser core. A desiccant bag mounted in the receiver/drier removes any retained moisture.
The manifold and tube assembly that mounts to the top of the receiver/drier contains the high-pressure service port for the refrigerant system.
A/C Pressure Transducer
The A/C pressure transducer monitors the compressor discharge pressure and communicates with the powertrain control module (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 no or 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 mounted on a Schrader valve-type fitting on the A/C compressor to condenser discharge line.
- A valve depressor, located inside the threaded end of the A/C pressure transducer, presses on the Schrader valve stem and allows the A/C pressure transducer to monitor the compressor discharge pressure.
- When the compressor discharge pressure rises, the PCM will interrupt the A/C compressor clutch coil circuit and disengage the A/C compressor. When the pressure drops, the PCM will enable the A/C compressor circuit. For specifications regarding operating pressure(s), refer to Computers and Control systems.
- It is not necessary to discharge the refrigerant system to remove the A/C pressure cutoff switch.
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 blacklight. 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 receiver/driers 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 receiver/drier 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, hose rupture, etc.
Spring Lock Coupling
Spring Lock Coupling:
When disconnecting or connecting spring lock couplings, observe the following.
- When the coupling is connected together, the flared end of the female fitting slips behind the garter spring inside the cage of the male fitting.
- The garter spring and cage then prevent the flared end of the female fitting from pulling out of the cage.
- Three O-ring seals are used to seal between the thermostatic expansion valve outlet tube and the compressor inlet tube. All other couplings have 2 O-ring seals.
- Use only the O-ring seals listed in the Ford Master Parts Catalog for the spring lock coupling.
- An A/C tube lock coupling clip is used to secure the coupling.
Peanut Fitting
Peanut Fitting:
When disconnecting or connecting peanut fittings, observe the following.
- The male and female blocks of the peanut fitting are retained with a nut.
- Support the female fitting with a wrench to prevent twisting of the tubes.
- An O-ring seal is installed around the tube on the male block.
- When correctly assembled, the male and female fittings should be flush.
- Use only the O-ring seal listed in the Ford Master Parts Catalog.
Service Gauge Port Valves
The high-pressure service gauge port valve is located on the A/C receiver/drier manifold and tube assembly.
The low-pressure service gauge port valve is located on the manifold of the A/C compressor manifold and tube assembly at the A/C compressor.
The fitting is an integral part of the refrigeration line or component.
- Special couplings are necessary 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 A/C charging valve cap removed, and is considered normal. A new Schrader-type valve core can be installed if the seal leaks excessively.
- The A/C charging valve caps are used as primary seals in the refrigerant system to prevent leakage through the Schrader-type valves from reaching the atmosphere. Always install and tighten the A/C charging valve caps to the correct torque after they are removed.
- Always install the A/C charging valve cap on service gauge port valves after repairing the refrigerant system.