Main Climate Control
AIR CONDITIONINGThe air conditioning system components are:
- A/C compressor
- A/C condenser core
- A/C evaporator core
- receiver/drier
- connecting refrigerant lines
- thermostatic expansion valve assembly
- A/C thermostatic switch
- Refrigerant containment switch
- A/C compressor pressure relief valve
- low charge protection switch
The refrigerant system incorporates an A/C compressor controlled by the powertrain control module (PCM) through an A/C clutch relay.
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 thermostatic switch is reading an acceptable temperature (4°C/39.5°F).
- The refrigerant containment switch is not open due to excessive pressure in the high side of the refrigerant system.
- The low charge protection switch is not open due to insufficient low side refrigerant system pressure.
- 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.
Refrigerant flow into the evaporator core is metered by a thermostatic expansion valve.
SC 115 Compressor Clutch:
A/C Compressor and Clutch Assembly
NOTE:
- Internal A/C compressor components are not serviced separately. The SC115 A/C compressor is serviced only as an assembly. The clutch plate, clutch pulley and bearing, and clutch field coil are serviceable.
- Installation of a new receiver/drier is not required when repairing the air conditioning system except when there is physical evidence of system contamination from a failed A/C compressor or damage to the receiver/drier.
- Vehicles equipped with Visteon fixed scroll A/C compressors may experience rapid refrigerant high side pressure fluctuations upon cold startups and/or after refrigerant system recharges. These high side refrigerant fluctuations are characteristic of the Visteon fixed scroll compressor and not an indication of a falling/failed A/C compressor.
The SC115 A/C compressor has [he following characteristics:
- Tangential mount design three lugs.
- The single manifold block of the compressor manifold and tube assembly fits to the suction and discharge ports. Two O-ring seals are used for sealing.
- An eccentric bushing is driven by the shaft of the A/C compressor.
- An orbiting scroll driven by the eccentric bushing compresses the refrigerant gas against the walls of the fixed scroll.
- Single reed-type discharge valve mounted on the back of the fixed scroll. There are no suction valves.
- Non-serviceable shaft seal fully supported on both sides by bearings.
- The A/C compressor uses PAG oil or equivalent. This oil contains special additives required for the A/C compressor.
- The A/C compressor oil from vehicles equipped with a SC115 A/C compressor may have some slightly dark-colored streaks while maintaining normal oil viscosity. This is normal for this A/C compressor because of break-in wear of the scroll seals that can discolor the oil.
- Use standard oil matching procedures when installing new compressors.
The magnetic A/C clutch has the following characteristics:
- It drives the compressor shaft.
- When battery voltage is applied to the A/C compressor clutch field coil, the clutch plate 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.
- 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.
Thermostatic Expansion Valve
The thermostatic expansion valve (TXV) is located between the evaporator core lines and the thermostatic expansion valve manifold and tube assembly at the RH 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 two 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.
Condenser Core
NOTE: Installation of a new receiver/drier is not required when repairing the air conditioning system except when there is physical evidence of system contamination from a failed A/C compressor or damage to the receiver/drier.
The 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
NOTE: Installation of a new receiver/drier is not required when repairing the air conditioning system except when there is physical evidence of system contamination from a failed A/C compressor or damage to the receiver/drier.
The compressor manifold and tube assembly is attached to the A/C compressor, is sealed with O-ring seals, and has the following features:
- The upstream side contains low pressure refrigerant gas.
- The downstream side contains high pressure refrigerant gas and a fitting used to mount a serviceable high-pressure A/C charge port valve. The downstream side contains a fitting used to mount the refrigerant containment switch. A long-travel Sebrader-type valve stem core is installed in the fitting so that the refrigerant containment switch can be removed without discharging the A/C system.
- The downstream side also contains a pressure relief valve.
Evaporator Core
NOTE:
- The evaporator core is not separately serviceable, it is serviced only with the evaporator core housing assembly.
- If an evaporator core leak is suspected, the evaporator core must be vacuum leak tested before it is removed from the vehicle.
- Installation of a new receiver/drier is not required when repairing the air conditioning system except when there is physical evidence of system contamination from a failed A/C compressor or damage to the receiver/drier.
The evaporator core is the plate/fin type with a unique refrigerant flow path.
- A mixture of refrigerant and oil enters the bottom of the evaporator core through the evaporator core inlet tube. continues over to the remaining five plate/fin sections, and then moves out of the evaporator core through the evaporator core outlet tube.
- This S-pass flow pattern accelerates the flow of refrigerant and oil through the evaporator core.
A/C Compressor Pressure Relief Valve
An A/C compressor pressure relief valve is incorporated in the compressor manifold and tube assembly to prevent damage to the A/C compressor and other system components. and to avoid total refrigerant loss by relieving unusually high refrigerant system discharge pressure buildups.
A/C Thermostatic Switch
The A/C thermostatic switch monitors the temperature of the refrigerant exiting the evaporator core into the TXV. It is used (by the PCM) to prevent freezing of the evaporator core by controlling A/C compressor clutch engagement/disengagement. Battery voltage is sent to the A/C thermostatic switch when the ignition switch is in the RUN position. The A/C thermostatic switch either supplies signal voltage to the PCM, or interrupts the signal voltage. A signal circuit connects the A/C thermostatic switch and the PCM and allows the PCM to monitor whether or not the signal voltage circuit is being completed by the A/C thermostatic switch. The PCM engages the A/C compressor clutch when the signal voltage is present and an A/C request has been received from the climate control assembly.
The A/C thermostatic switch is mounted on the TXV. Thermal grease must be applied to the A/C thermostatic switch probe when installing it into the TXV.
Low Charge Protection Switch
CAUTION: It is necessary to recover the refrigerant from the A/C system before removing the low charge protection switch.
The low charge protection switch is used to prevent A/C compressor damage in the event of a low refrigerant charge, by interrupting the ground signal circuit between the refrigerant containment switch and ground, when the low side refrigerant pressure drops below acceptable levels. The electrical switch contacts open when the suction pressure drops below normal levels. The Contacts close when the suction pressure rises.
The low charge protection switch is mounted on the TXV.
Refrigerant Containment Switch
The refrigerant containment switch is used to interrupt A/C compressor operation in the event of high system discharge pressures.
- The refrigerant containment switch is mounted on a Schrader valve-type fitting on the high pressure side of the compressor manifold and tube assembly.
- A valve depressor, located inside the threaded end of the refrigerant containment switch, presses on the Schrader valve stem.
- This allows the refrigerant containment switch to monitor the A/C compressor discharge pressure.
- When the A/C compressor discharge pressure rises, the switch contacts open, disengaging the A/C compressor. When the pressure drops, the contacts close to allow operation of the A/C compressor.
- It is not necessary to discharge the refrigerant system to remove the refrigerant containment switch.
Spring Lock Coupling:
Spring lock coupling
The spring lock coupling is a refrigerant line coupling held together by a garter spring inside a circular cage.
- 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 two halves of the couplings.
- Use only the O-ring seals listed in the Ford Master Parts Catalog for the spring lock coupling.
- A plastic indicator ring is used on the spring lock couplings of the evaporator core to indicate, during vehicle assembly, that the coupling is connected. Once the coupling is connected, the indicator ring is no longer necessary but will remain captive by the coupling near the cage opening.
- The indicator ring may also be used during service operations to indicate connection of the coupling.
- An A/C tube lock coupling clip may be used to secure the coupling but is not required.
Peanut Fitting
The condenser core uses peanut-shaped refrigerant fittings instead of spring lock couplings.
- The male and female blocks of the peanut fitting are retained with a nut.
- An O-ring seal is installed around the tube on the male block.
- Support the female fitting with a wrench to prevent twisting of the tubes.
- When correctly assembled, the male and female fittings should be flush.
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 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 filtering separation, hose rupture or other damage.