2003 FORD MUSTANG air conditioning

If two substances of different temperature are placed near each other, the heat in the warmer
substance will transfer to the colder substance.
Latent Heat of Vaporization
When a liquid boils (converts to a gas), it absorbs heat without raising the temperature of the resulting
gas. When the gas condenses (reverts back to a liquid), it gives off heat without lowering the
temperature of the resulting liquid.
Relative Humidity
The amount of moisture (water vapor content) that the air can hold is directly related to the air
temperature. The more heat there is in the air, the more moisture the air can hold. The lower the
moisture content in the air, the more comfortable you feel. Removing moisture from the air lowers its
relative humidity and improves personal comfort.
Effects of Pressure on Boiling or Condensation
As the pressure is increased on a liquid, the temperature at which the liquid boils (converts to a gas)
also increases. Conversely, when the pressure on a liquid is reduced, its boiling point is also reduced.
When in the gas state, an increase in pressure causes an increase in temperature, while a decrease in
pressure will decrease the temperature of the gas.
Compressor Anti-
Slugging Strategy
Liquid refrigerant may accumulate in the A/C compressor under certain conditions. To alleviate
damage to the A/C compressor, compressor anti- slugging strategy (CASS) is utilized.
CASS is initiated only under specific conditions:
zthe ignition is off for more than 8 hours
z the ambient temperature is above -4º C (25ºF)
z battery voltage is above 8.5 volts during engine cranking
When these conditions are present, the powertrain control module (PCM) will activate the A/C control
relay prior to cranking of the engine. The A/C control relay engages the A/C compressor for
approximately 4- 15 A/C compressor revolutions or a maximum of 2 seconds (depending upon vehicle
application), allowing the liquid refrigerant to be pushed from the A/C compressor. CASS is initiated by
the PCM regardless of the function selector switch position or the EATC system settings.
The Refrigerant Cycle
During stabilized conditions (air conditioning system shut down), the refrigerant is in a vaporized state
and pressures are equal throughout the system. When the A/C compressor (19703) is in operation, it
increases pressure on the refrigerant vapor, raising its temperature. The high- pressure and high-
temperature vapor is then released into the top of the A/C condenser core (19712).
The A/C condenser core, being close to ambient temperature, causes the refrigerant vapor to
condense into a liquid when heat is removed from the refrigerant by ambient air passing over the fins
and tubing. The now liquid refrigerant, still at high pressure, exits from the bottom of the A/C
condenser core and enters the inlet side of the A/C evaporator core orifice (19D990).
The A/C evaporator core orifice is the restriction in the refrigerant system that creates the high
pressure buildup upstream of the A/C evaporator core (19860) and separates the high and low
pressure sides of the A/C system. As the liquid refrigerant leaves this restriction, its pressure and
boiling point are reduced.
The liquid refrigerant is now at its lowest pressure and temperature. As it passes through the A/C Klj . 3 ba
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PINPOINT TEST E: INSUFFICIENT A/C COOLING C294c-
3, circuit 348 (PK), harness side and ground.
z Is there voltage present? No
INSTALL a new function
selector switch. REFER to
Section 412
- 04 . TEST the
system for normal operation. D5 CHECK FOR A SHORTED CLUTCH INPUT
z
Key in OFF position.
z Disconnect: A/C Clutch C100.
z Key in ON position.
z Measure for voltage at the A/C clutch C100, circuit 347
(BK/YE), harness side and ground.
z Is there voltage present? Yes
INSTALL a new constant
control relay module. TEST the
system for normal operation.
No
CHECK the clutch air gap.
REFER to
Air Conditioning (A/C) Clutch Air Gap
Adjustment .
Test Step Result / Action to Take
E1 CHECK THE CENTER A/C REGISTER DISCHARGE
TEMPERATURE z
Carry out the refrigerant system tests. Refer to
Refrigerant System Tests in this section.
z Use the recorded data from the refrigerant system tests
to plot a vertical line for ambient temperature and a
horizontal line for center A/C register discharge
temperature.
z Is the intersection of the two lines within the upper
and lower limits? Yes
The tests indicate that the
system is functioning normally.
No
GO to
E2 . Klj . 25 ba
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to plot a vertical line for ambient temperature and a
horizontal line for A/C clutch OFF time in seconds.
z Is the intersection of the two lines above the upper
limit? DISCHARGE and RECOVER
the system to remove
excessive moisture or
refrigerant oil. REFER to
Air Conditioning (A/C) System
Recovery, Evacuation and
Charging . TEST the system
for normal operation.
No
GO to E7 .
E6 CHECK FOR A HIGH SUCTION PRESSURE
z
Refer to the data plot used to evaluate the system low
pressure performance in Step E3.
z Is the intersection of the two lines above the upper
limit? Yes
REMOVE the A/C evaporator
core orifice to repair missing or
damaged (leaking) O-
ring
seals. REFER to Section 412 -
03 . TEST the system for
normal operation.
No
INSTALL a new A/C cycling
switch when the intersection of
the two lines is below the
lower limit. REFER to Section 412 - 03 . TEST the system for
normal operation. E7 CHECK THE AMBIENT TEMPERATURE
z
Refer to the data plot used to evaluate the system A/C
clutch OFF time in Step E5.
z Is the ambient temperature above 26°C (80°F)? Yes
This is normal operation for
the refrigerant system in high
humidity conditions.
No
DISCHARGE and RECOVER
the system to correct an
overcharge condition. REFER
to
Air Conditioning (A/C) System Recovery, Evacuation
and Charging . TEST the
system for normal operation. E8 CHECK FOR A HIGH DISCHARGE PRESSURE
z
Refer to the data plot used to evaluate the system high
pressure performance in Step E2.
z Is the intersection of the two lines above the upper
limit? Yes
GO to
E9 .
No
GO to E11 .
E9 CHECK FOR A NORMAL LOW PRESSURE
z
Use the recorded data from the refrigerant system tests
to plot a vertical line for ambient temperature and a
horizontal line for compressor suction (low) pressure. Yes
REFER to
Section 303 - 03A or
Section 303 - 03B . to diagnose
the engine cooling system.
TEST the system for normal
operation. Klj . 27 ba
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z
Is the intersection of the two lines above the upper
limit? E13 CHECK FOR A NORMAL A/C CLUTCH OFF TIME
z
Use the recorded data from the refrigerant system tests
to plot a vertical line for ambient temperature and a
horizontal line for A/C clutch OFF time in seconds.
z Is the intersection of the two lines within the upper
and lower limits? Yes
INSPECT the A/C evaporator
core due to a low or restricted
airflow. TEST the system for
normal operation.
No
GO to
E14 .
E14 CHECK FOR A LONG A/C CLUTCH OFF TIME
z
Refer to the data plot used to evaluate the system A/C
clutch OFF time performance in Step E13.
z Is the intersection of the two lines above the upper
limit? Yes
INSTALL a new A/C
condenser core due to a
partially restricted or plugged
condition. REFER to
Section 412 - 03 . TEST the system for
normal operation.
No
EVACUATE and RECHARGE
the system when the
intersection of the two lines is
below the lower limit. REFER
to Air Conditioning (A/C) System Recovery, Evacuation
and Charging . TEST the
system for normal operation. E15 CHECK FOR A MISSING A/C EVAPORATOR CORE
ORIFICE z
Remove the A/C evaporator core orifice tube. Refer to
Section 412 - 03 .
z Is the A/C evaporator core orifice missing? Yes
INSTALL a new A/C
evaporator core orifice.
REFER to
Section 412 - 03 .
TEST the system for normal
operation.
No Klj . 29 ba
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A/C Evaporator/Condenser Core—
On-Vehicle Leak Test
1. Discharge and recover the refrigerant. For additional information, refer to Air Conditioning (A/C) System Recovery, Evacuation and Charging in this section.
2. NOTE: DO NOT leak test an A/C evaporator core with the suction accumulator/drier (19C836)
attached to the core tubes.
Disconnect the suspect A/C evaporator core or A/C condenser core from the A/C system. For
additional information, refer to Section 412 - 03 .
3. Clean the spring lock couplings. For additional information, refer to Spring Lock Coupling in this
section.
4. Connect the appropriate test fittings from the A/C Test Fitting Set to the evaporator or condenser tube connections.
5. NOTE: The automatic shut- off valves on some gauge set hoses do not open when connected to
the test fittings. If available, use hoses without shut- off valves. If hoses with shut-off valves are
used, make sure the valve opens when attached to the test fittings or install an adapter which
will activate the valve. The test is not valid if the shut- off valve does not open.
Connect the red and blue hoses from the manifold gauge set to the test fittings on the A/C
evaporator core or A/C condenser core. Connect the yellow hose to a known good vacuum
pump.
6. Open both gauge set valves and start the vacuum pump. Allow the vacuum pump to operate for a minimum of 45 minutes after the gauge set low pressure gauge indicates 101 kPa (30 in- Hg).
The 45- minute evacuation is necessary to remove any refrigerant from oil left in the A/C
evaporator core or A/C condenser core. If the refrigerant is not completely removed from the oil,
outgassing will degrade the vacuum and appear as a refrigerant leak.
7. If the low pressure gauge reading will not drop to 101 kPa (30 in- Hg) when the valves on the
gauge and manifold set are open and the vacuum pump is operating, close the gauge set
valves and observe the low pressure gauge. If the pressure rises rapidly to zero, a large leak is
indicated. Recheck the test fitting connections and gauge set connections before installing a
new A/C evaporator core or A/C condenser core.
8. After evacuating for 45 minutes, close the gauge set valves and stop the vacuum pump. Observe the low pressure gauge; it should remain at the 101 kPa (30 in- Hg) mark.
z If the low pressure gauge reading rises 34 or more kPa (10 or more in- Hg) of vacuum
from the 101 kPa (30 in- Hg) position in 10 minutes, a leak is indicated.
z If a very small leak is suspected, wait 30 minutes and observe the vacuum gauge.
z If a small amount of vacuum is lost, operate the vacuum pump with gauge valves open
for an additional 30 minutes to remove any remaining refrigerant from the oil in the A/C Klj . 39 ba
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evaporator core or A/C condenser core. Then recheck for loss of vacuum.
z If a very small leak is suspected, allow the system to sit overnight with vacuum applied
and check for vacuum loss.
9. If the A/C evaporator core or A/C condenser core does leak, as verified by the above procedure, install a new A/C evaporator core or A/C condenser core. For additional information, refer to
Section 412 - 03 .
A/C Compressor— External Leak Test
1. Install the A/C pressure test adapter on the rear head of the A/C compressor using the existing manifold retaining bolt.
2. Connect the high and low pressure lines of a manifold gauge set or a refrigerant recovery/recycling station such as the R- 134a A/C Service Center to the corresponding fittings
on the A/C pressure test adapter.
3. Attach the center hose of the manifold gauge set to a refrigerant container standing in an upright position.
4. Hand- rotate the compressor shaft 10 complete revolutions to distribute the oil inside the A/C
compressor.
5. Open the low pressure gauge valve, the high pressure gauge valve and the valve on the refrigerant container to allow the refrigerant vapor to flow into the A/C compressor.
6. Using the Refrigerant Leak Detector, check for leaks at the compressor shaft seal and the compressor center seal.
7. If a shaft seal leak is found, install a new shaft seal. For additional information, refer to Section 412 - 03 . If an external leak is found at the center joint of the A/C compressor, install a new A/C
compressor.
8. When the leak test is complete, recover the refrigerant. For additional information, refer to Air Conditioning (A/C) System Recovery, Evacuation and Charging in this section. Klj . 40 ba
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GENERAL PROCEDURES
Air Conditioning (A/C) System Check —
Retail Procedure
NOTE: This Retail Procedure is not eligible for claiming on Ford paid repairs (warranty and ESP).
NOTE: The engine should be run at idle for 10 minutes with the air conditioning on and set to MAX A/C
before carrying out this retail procedure.
NOTE: Read and follow all of the Warnings, Cautions and Notes at the beginning of this section before
continuing.
1. Visual inspection
Open the hood and visually inspect the heating and air conditioning systems for the following:
zCoolant reservoir for correct coolant level
z Heater hoses for deterioration or loose connections
z Radiator and condenser for debris or damaged fins restricting airflow, loose mounting or
connections
z Accessory drive belt(s) and cooling fan(s) for wear or physical damage
z Refrigerant lines and connections for physical damage or loose connections
z Compressor for physical damage or loose connections
z Suction accumulator/drier for physical damage or loose connections
z Wiring and connectors for excessive wear, loose or damaged connections, or incorrect
routing
2. A/C refrigerant analysis
zCarry out air conditioning refrigerant analysis. For additional information, refer to
Refrigerant Identification Testing in this section.
z If the refrigerant fails the analysis, discontinue diagnosis and make recommendations for
repairs.
z If the refrigerant passes the analysis, carry out the air conditioning system check.
3. Air conditioning system check
zConnect manifold gauge set or charging station with gauges to refrigerant system.
z With the vehicle in park, parking brake set, thermometer installed in center panel vent,
and air conditioning system on and set to MAX A/C, start the engine.
z Record air refrigerant system pressures while running the engine at 1,500 rpm and allow
engine to return to idle.
z Operate the blower motor in all control positions and check for correct blower speed
changes.
z With the blower motor on HI, operate air discharge mode selector in all positions and
check for correct airflow in each position.
z Operate the temperature blend selector in all positions and check for correct change in
discharge temperature. Check the air discharge temperature with the selector in the
coolest position and the air conditioning on and set to MAX A/C to determine if the air
discharge temperature is acceptable for the current ambient air temperature.
z Carry out the EATC self- test (if applicable).
If the refrigerant system pressures were low, carry out the refrigerant system leak test.
SECTION 412-
00: Climate Control System - General Information 2003 Mustang Workshop Manual Klj . 1 ba
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GENERAL PROCEDURES
Air Conditioning Line (Peanut) Fitting
Disconnect
1. CAUTION: Support the female fitting with a wrench to prevent the tubes from
twisting.
Remove the nut from the peanut fitting.
2. Pull the peanut fitting apart.
3. CAUTION: Do not use metal tools to remove the O- ring seal. They can cause axial
scratches across the O- ring seal groove, resulting in refrigerant leaks.
Remove the O- ring seal with a non- metallic tool.
SECTION 412-
00: Climate Control System - General Information 2003 Mustang Workshop Manual Klj . 1 ba
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