HVAC System: Other Ford Taurus IV facelift

Air Conditioning

The A/C refrigerant system is a clutch cycling orifice tube type. The system components include

1. A/C compressor (19703)
2. A/C clutch assembly
3. A/C condenser core (19712)
4. A/C evaporator core (19860)
5. A/C suction accumulator (19C836)
6. Connecting refrigerant lines

The refrigeration system operation is controlled by the

1. A/C evaporator core orifice (19D990)
2. Evaporator air discharge temperature sensor (19C734)
3. A/C compressor pressure relief valve (19D644)
4. Dual function pressure switch (19D594)
5. Low charge protection switch (19E561)

The refrigerant system incorporates an A/C compressor controlled by an evaporator air discharge temperature sensor.

The evaporator air discharge temperature sensor senses the A/C evaporator core temperature to control A/C compressor operation. For additional information concerning the evaporator air discharge temperature sensor, refer to CONTROL COMPONENTS .

An A/C pressure relief valve is installed in the A/C manifold and tube (19D734) to protect the refrigerant system against excessively high refrigerant pressures.

The A/C evaporator core orifice is installed in the condenser to evaporator tube (19835) to meter the liquid refrigerant into the A/C evaporator core.

A/C Compressor Pressure Relief Valve

An A/C pressure relief valve (19D644) is incorporated in the compressor manifold and tube to

1. Relieve unusually high refrigerant system discharge pressure buildups. For specifications regarding operating pressure(s), refer to «CLIMATE CONTROL SYSTEM-GENERAL INFORMATION»(ref-212118) .
2. Prevent damage to the A/C compressor and other system components.
3. Avoid total refrigerant loss by closing after the excessive pressure has been relieved.

A/C Condenser Core

Note. Installation of a new suction accumulator 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 suction accumulator.

The A/C condenser core has the following characteristics

1. It is an aluminum fin and tube design heat exchanger located in front of the vehicle radiator (8005).
2. It cools compressed refrigerant gas by allowing air to pass over the fins and tubes to extract heat and by condensing gas to liquid refrigerant as it is cooled.

A/C Evaporator Core

Note. Installation of a new suction accumulator 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 suction accumulator.

Note. The evaporator core is serviced as a core and housing assembly. The evaporator core, internal doors, seals and door linkage are included with the housing.

The A/C evaporator core is the plate/fin type.

1. The A/C evaporator core is located inside the vehicle in the evaporator core housing.
2. A mixture of refrigerant and oil enters the bottom of the A/C evaporator core through the A/C evaporator core inlet tube and then moves out of the A/C evaporator core through the A/C evaporator core outlet tube.
3. During A/C operation, air from the blower motor is cooled and dehumidified as it passes through the evaporator core fins.

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Note. A new A/C evaporator core orifice should be installed whenever a new A/C compressor is installed.

The A/C evaporator core orifice (19D990) has the following characteristics

1. It is located in the aft condenser to evaporator tube.
2. It has filter screens located on the inlet and outlet ends of the tube body.
3. The inlet filter screen acts as a strainer for the liquid refrigerant flowing through the A/C evaporator core orifice.
4. O-ring seals on the A/C evaporator core orifice prevent the high-pressure liquid refrigerant from bypassing the A/C evaporator core orifice.
5. Adjustment or repair cannot be made to the A/C evaporator core orifice assembly. It must be installed as a unit. The evaporator core orifice can be accessed by separating a tube-O fitting in the condenser to evaporator line.

An A/C evaporator core orifice or O-ring seal is not considered a major component but a new A/C evaporator core orifice should be installed whenever a new A/C compressor is installed for lack of performance.

Suction Accumulator

Note. Installation of a new suction accumulator 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 suction accumulator.

A new suction accumulator (19C836) should be installed if one of the following conditions exists

1. The suction accumulator is perforated.
2. There is evidence of moisture in the system such as internal corrosion of metal refrigerant lines or the refrigerant oil is thick and dark.

The suction accumulator is mounted to the A/C accumulator bracket (19D606) to the right of the vehicle centerline. The inlet tube of the suction accumulator is attached to the evaporator to accumulator suction line. The outlet tube attaches to the evaporator to compressor suction line (19D742).

After entering the inlet of the suction accumulator, heavier oil-laden refrigerant contacts an internally mounted dome (which serves as an umbrella) and drips down onto the bottom of the canister.

1. A small diameter oil bleed hole, in the bottom of the vapor return tube, allows the accumulated heavier liquid refrigerant and oil mixture to re-enter the compressor suction line at a controlled rate.
2. As the heavier mixture passes through the small diameter liquid bleed hole, it has a second chance to vaporize and recirculate through the A/C compressor without causing compressor damage due to slugging.
3. A fine mesh screened filter fits tightly around the bottom of the vapor return tube to filter out refrigerant system contaminant particles.
4. A desiccant bag is mounted inside the canister to absorb any moisture which may be in the refrigerant system.
5. A fitting located on the top of the suction accumulator is used to attach the low charge protection switch. A long-travel Schrader-type valve system core is installed in the fitting so that the low charge protection switch can be removed without recovering the refrigerant.

Low Charge Protection Switch

The low charge protection switch (19E561) is used to prevent A/C compressor damage in the event of a low refrigerant charge.

1. The electrical switch contacts open when the suction pressure drops below normal levels. The contacts close when the suction pressure rises. For specifications regarding operating pressure(s), refer to «CLIMATE CONTROL SYSTEM-GENERAL INFORMATION»(ref-212118) .
2. When the low charge protection switch contacts open, the A/C clutch field coil is de-energized and compressor operation stops.
3. The low charge protection switch is mounted on a Schrader-type valve fitting on the top of the suction accumulator.
4. A valve depressor, located inside the threaded end of the low charge protection switch, presses in on the Schrader valve stem, allowing the suction pressure inside the suction accumulator to control the operation of the low charge protection switch.
5. It is not necessary to recover the refrigerant to remove the low charge protection switch.

Dual Function Pressure Switch

The dual function pressure switch (19D594) is used to interrupt A/C compressor operation in the event of high system discharge pressures.

1. The dual function pressure switch is mounted on a schrader-type valve fitting on the compressor manifold and tube assembly.
2. It is not necessary to recover the refrigerant when removing the dual function pressure switch.
3. A valve depressor, located in the threaded end of the dual function pressure switch, presses on the Schrader-type valve stem. This allows the dual function pressure switch to monitor the compressor discharge pressure.
4. When the compressor discharge pressure rises, the switch contacts open, disengaging the A/C compressor. When the compressor discharge pressure drops, the switch contacts close to allow operation of the A/C compressor. For specifications regarding operating pressure(s), refer to «CLIMATE CONTROL SYSTEM-GENERAL INFORMATION»(ref-212118) .
5. The dual function pressure switch has a second set of electrical contacts used for high-speed cooling fan control. When the compressor discharge pressure rises, the contacts close and engage the high-speed cooling fan control. When the pressure drops, the contacts open and the high-speed cooling fan control is disengaged. For additional information, refer to «ENGINE COOLING»(ref-212100) .

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When disconnecting or connecting spring lock couplings, observe the following.

1. 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.
2. The garter spring and cage then prevent the flared end of the female fitting from pulling out of the cage.
3. Three O-ring seals are used to seal between the two halves of the couplings.
4. Use only the O-ring seals listed in the Ford Master Parts Catalog for the spring lock coupling.
5. A plastic indicator ring is used 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.
6. The indicator ring may also be used during service operations to indicate connection of the coupling.
7. An A/C tube lock coupling clip (19E746) may be used to secure the coupling but is not required.

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When disconnecting or connecting peanut fittings, observe the following.

1. The male and female blocks of the peanut fitting are retained with a nut.
2. Support the female fitting with a wrench to prevent twisting of the tubes.
3. An O-ring seal is installed around the tube on the male block.
4. When correctly assembled, the male and female fittings should be flush.
5. Use only the O-ring seal listed in the Ford Master Parts Catalog.

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When disconnecting or connecting tube-O fittings, observe the following.

1. The male and female portions of the fitting are retained with a nut.
2. Support the female fitting with a wrench to prevent twisting of the tubes when disconnecting.
3. An O-ring seal is installed around the tube on the male side of the fitting.
4. Use only the O-ring seal listed in the Ford Master Parts Catalog.

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The high-pressure service gauge port valve is located on the high pressure liquid line.

The low pressure service gauge port valve is located on the evaporator to suction accumulator line.

The fitting is an integral part of the refrigerant line or component.

1. R-134a type service couplings are required for both the high side and low side service gauge ports.
2. A new Schrader-type valve core can be installed if the seal leaks.
3. Always install the A/C charging valve cap (19D702) on the service gauge port valves after repairing the refrigerant system.

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 fitting separation, hose rupture, etc. For additional information, refer to CLIMATE CONTROL SYSTEM-GENERAL INFORMATION .

Refer to CLIMATE CONTROL SYSTEM-GENERAL INFORMATION .

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