AC system FORD MUSTANG 2003 Workshop Manual

DESCRIPTION AND OPERATION
Climate Control System
WARNING: To avoid accidental deployment and possible injury, the air bag system
backup power supply must be depleted before repairing any climate control components. To
deplete the backup power supply, disconnect the battery ground cable and wait one minute.
Failure to follow these instructions may result in personal injury.
WARNING: Carbon monoxide is colorless, odorless and dangerous. If it is necessary to
operate the engine with the vehicle in a closed area such as a garage, always use an exhaust
collector to vent the exhaust gases outside the closed area.
WARNING: R- 134a is classified as a safe refrigerant, but misuse can make it dangerous.
The following precautions must be observed:
zAlways wear safety goggles when repairing an air conditioning system.
z Avoid contact with liquid refrigerant R- 134a. R-134a vaporizes at approximately - 25°C (-
13°F) under atmospheric pressure and it will freeze skin tissue.
z Never allow refrigerant R- 134a gas to escape in quantity in an occupied space. R- 134a is
non- toxic, but it will displace the oxygen needed to support life.
z Never use a torch in an atmosphere containing R- 134a gas. R-134a is non-toxic at all
normal conditions, but when it is exposed to high temperatures, such as a torch flame, it
decomposes. During decomposition it releases irritation and toxic gases (as described in
the MSDS sheet from the manufacturer). Decomposition products are hydrofluoric acid,
carbon dioxide and water.
z Do not allow any portion of the charged air conditioning system to become too hot. The
pressure in an air conditioning system rises as the temperature rises and temperatures
of approximately 85°C (185°F) can be dangerous.
z Allow the engine to cool sufficiently prior to carrying out maintenance or serious burns
and injury can occur.
CAUTION: To avoid damaging the vehicle or A/C components, the following precautions
must be observed:
zThe A/C refrigerant of all vehicles must be identified and analyzed prior to refrigerant
charging. Failure to due so can contaminate the shop bulk refrigerant and other vehicles.
z Do not add R- 12 refrigerant to an A/C system that requires the use of R- 134a refrigerant.
These two types of refrigerant must never be mixed. Doing so can damage the A/C
system.
z Charge the A/C system with the engine running only at the low- pressure side to prevent
refrigerant slugging from damaging the A/C compressor.
z Use only R- 134a refrigerant. Due to environmental concerns, when the air conditioning
system is drained, the refrigerant must be collected using refrigerant recovery/recycling
equipment. Federal law REQUIRES that R- 134a be recovered into appropriate recovery
equipment and the process be conducted by qualified technicians who have been
certified by an approved organization, such as MACS, ASI etc. Use of a recovery machine
dedicated to R- 134a is necessary to reduce the possibility of oil and refrigerant
incompatibility concerns. Refer to the instructions provided by the equipment manufacturer when removing refrigerant from or charging the air conditioning system. SECTION 412-
00: Climate Control System - General Information 2003 Mustang Workshop Manual Klj . 1 ba
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z
Refrigerant R- 134a must not be mixed with air for leak testing or used with air for any
other purpose above atmospheric pressure. R- 134a is combustible when mixed with high
concentrations of air and higher pressures.
z A number of manufacturers are producing alternative refrigerant products that are
designed to be used instead of R- 134a refrigerant. The use of any unauthorized
substitute refrigerant can severely damage the A/C components. If repair is required, use
only new or recycled refrigerant R- 134a.
CAUTION: To avoid contamination of the A/C system, always observe the following:
z Keep service tools and the work area clean.
z Never open or loosen a connection before discharging the system.
z When loosening a connection, if any residual pressure is evident, allow it to leak out
before opening the fitting.
z Evacuate a system that has been opened to install a new component or one that has
been discharged through leakage before charging.
z Seal an open fitting with a cap or plug immediately after disconnecting a component
from the system.
z Clean the outside of the fittings thoroughly before disconnecting a component from the
system.
z Do not remove the sealing caps from a new component until ready to install.
z Refrigerant oil will absorb moisture from the atmosphere if left uncapped. Do not open
an oil container until ready to use, and install the cap immediately after using. Store the
oil in a clean, moisture- free container.
z Install a new O- ring seal before connecting an open fitting. Coat the fitting and the O- ring
seal with refrigerant oil before connecting.
z When installing a refrigerant line, avoid sharp bends. Position the line away from the
exhaust or any sharp edges that can chafe the line.
z Do not open a refrigerant system or uncap a new component unless it is as close as
possible to room temperature. This will prevent condensation from forming inside a
component that is cooler than the surrounding air.
The manual climate control system heats or cools the vehicle depending on the function selector
switch position and the temperature selected.
zThe function selector switch position determines heating or cooling and air distribution.
z The temperature control setting determines the air temperature.
z The heater blower motor switch (18578) varies the blower motor speed.
Principles of Operation
There are four main principles involved with the basic theory of operation:
zheat transfer
z latent heat of vaporization
z relative humidity
z effects of pressure Heat Transfer Klj . 2 ba
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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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evaporator core, it absorbs heat from the passenger compartment airflow passing over the plate/fin
sections of the A/C evaporator core. This addition of heat causes the refrigerant to boil (convert to a
gas). The now cooler passenger compartment air can no longer support the same humidity level of the
warmer air and this excess moisture condenses on the exterior of the evaporator coils and fins and
drains outside the vehicle.
The suction accumulator/drier (19C836) is designed to remove moisture from the refrigerant and to
prevent any liquid refrigerant that may not have been vaporized in the A/C evaporator core from
reaching the A/C compressor. The A/C compressor is designed to pump refrigerant vapor only, as
liquid refrigerant will not compress and can damage the A/C compressor.
The refrigerant cycle is now repeated with the A/C compressor again increasing the pressure and
temperature of the refrigerant.
The A/C cycling switch (19E561) interrupts compressor operation before the external temperature of
the A/C evaporator core gets low enough to cause the condensed water vapor (excess humidity) to
turn to ice. It does this by monitoring low side line pressure. It is known that a refrigerant pressure of
approximately 210 kPa (30 psi) will yield an operating temperature of 0°C (32°F). The A/C cycling
switch controls system operation in an effort to maintain this temperature.
The high side line pressure is also monitored so that the A/C compressor operation can be interrupted
if system pressure becomes too high.
The A/C compressor pressure relief valve (19D644) will open and vent refrigerant to relieve unusually
high system pressure.
Clutch Cycling Orifice Tube Type Refrigerant System Klj . 4 ba
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System Air Flow Description
MAX A/C
When MAX A/C is selected:
zThe air inlet door vacuum control motor is at full vacuum, closing off outside air and admitting
only recirculated air.
z The panel/defrost door vacuum control motor is at full vacuum and the panel/floor door vacuum
control motor is at no vacuum, directing airflow to the instrument panel A/C registers. A small
amount of airflow from the side window demisters will be present.
z Blended air temperature is available.
z The A/C compressor will operate if the outside temperature is above approximately 6°C (43°F).
z The blower motor is on.
NORM A/C
When NORM A/C is selected:
zThe air inlet door vacuum control motor is at no vacuum, admitting only outside air into the
passenger compartment. 9 19D990 A/C evaporator core orifice
10 19860 A/C evaporator core
11 — Low pressure vapor
12 — High pressure vapor
13 — Low pressure liquid
14 — High pressure liquid Klj . 6 ba
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DIAGNOSIS AND TESTING
Climate Control System
Refer to Wiring Diagrams Cell
54 , Air Conditioner/Heater for schematic and connector information.
SECTION 412-
00: Climate Control System - General Information 2003 Mustang Workshop Manual Special Tool(s)
Connector, Refrigerant
Pressure Line
412-
093 (T94P-19623- E) Set, A/C Fittings
412-
DS028 (014- 00333, D93L-
19703- B) or equivalent Vacuum Pump Kit
416-
D002 (D95L-7559- A) or
equivalent Breakout Box, EEC-V Control
System
418- 049 (014-00950, T94L-50-
EEC- V) Worldwide Diagnostic System
(WDS)
418-
F224,
New Generation STAR (NGS)
Tester
418- F052, or equivalent
diagnostic tool Pressure Test Kit
014-
R1072 or equivalent 77 III Automotive Meter
105-
R0056 or equivalent Klj . 1 ba
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Vacuum Schematic — Manual Climate Control System R-
134a Manifold Gauge Set
176- R032A or equivalent Refrigerant Leak Detector
216-
00001 or equivalent Klj . 2 ba
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Function Selector Switch Vacuum Connector
V=Vacuum
NV=No Vacuum
Inspection and Verification
1. Verify the customer's concern by operating the climate control system to duplicate the condition. 16 18476 Heater core
17 18A559 Panel/floor door (full vacuum position)
18 — Floor airflow
19 18A318 Vacuum control motor—
floor/panel door 20 — Panel vent airflow
Port No. Hose Color Function
1 White Air inlet door
2 Red Panel/floor door
3 Blue Panel/floor door
4 Yellow Panel/defrost door
5 Black Vacuum source
6 — Not used
Function Selector Switch Vacuum Application Chart Switch Port Color Function Function Selector Switch Position
MAX A/C A/C Vent OFF Floor FLR/ DEF Defrost
1 White Recirc/Fresh V NV NV V NV NV NV
2 Red Floor NV NV NV V V NV NV
3 Blue Panel/floor NV NV NV V V V NV
4 Yellow Panel/defrost V V V NV NV NV NV
5 Black Vacuum source V V V V V V V Klj . 4 ba
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2. Inspect to determine if one of the following mechanical or electrical concerns apply:
a A leak in the vacuum control circuit may occur during acceleration (slow leak), at all times
(large leak), or only when specific functions are selected (indicating a leak in that portion of the
circuit). The vacuum hoses used in the passenger compartment control circuit are constructed
from PVC plastic material. The vacuum hoses used in the engine compartment are constructed
of Hytrel® . Because of the materials used, never pinch the vacuum hoses off during diagnosis
to locate a leak. A wood golf tee can be used as a plug when it is necessary to plug one end of
a vacuum hose for leak test purposes.
3. If the inspection reveals obvious concerns that can be readily identified, repair as required.
4. If the concern remains after the inspection, connect the scan tool to the data link connector (DLC) located beneath the instrument panel and select the vehicle to be tested from the scan
tool menu. If the vehicle selection cannot be entered:
zcheck that the program card is correctly installed.
z check the connections to the vehicle.
z check the ignition switch position.
If the scan tool still does not allow the vehicle selection to be entered, refer to the scan tool manual. 5. Carry out the DATA LINK DIAGNOSTIC TEST using the scan tool. If the scan tool responds with:
zCKT 914, CKT 915 or CKT 70 = ALL MODULE NO RESPONSE/NOT EQUIPPED, go to
Communication System Diagnostics in Section 418 - 00 to diagnose network concern.
z If the powertrain control module (PCM) is not listed for a communication concern, turn
the A/C function selector switch to OFF and execute self- test diagnostics for the PCM.
6. If any PCM DTCs are retrieved, and are related to the concern, go to the Powertrain Control Module Diagnostic Trouble Code (DTC) Index to continue diagnostics.
7. If no DTCs related to the concern are retrieved, go to the Symptom Chart to continue diagnostics.
Symptom Chart Visual Inspection Chart Mechanical Electrical
z
Loose, missing or damaged A/C compressor
drive belt.
z Loose or disconnected A/C clutch.
z Loose, misrouted or damaged vacuum lines. a
z Broken or leaking refrigerant lines.
z Broken or leaking vacuum control motor. z
Open fuses.
z Blower motor inoperative.
z A/C compressor inoperative.
z Circuitry open/shorted.
z Disconnected electrical
connectors.
Powertrain Control Module Diagnostic Trouble Code (DTC) Index DTC Description Action
P1460 WOT A/C cutout circuit
malfunction Refer to the Powertrain Control/Emissions Diagnosis
(PC/ED) manual.
P1464 A/C demand out of self-
test
range GO to DTC P1464. Klj . 5 ba
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Symptom Chart
Condition
Possible Sources Action
z Incorrect/erratic direction
of airflow from outlet(s) z
No vacuum to A/C heater
function switch selector.
z A/C heater function selector
switch leaks vacuum.
z Kinked/pinched vacuum hose.
z Leaking vacuum control
motor.
z Leaking A/C vacuum check
valve.
z Leaking A/C vacuum reservoir
tank and bracket.
z Vacuum actuator arm not
connected to door crank. z
Go To Pinpoint
Test A .
z Insufficient, erratic, or no
heat z
Low engine coolant level.
z Thermostat stuck open.
z Disengaged/damaged
temperature cable. z
Go To Pinpoint
Test B .
z The A/C does not
operate/does not operate
correctly z
CASS strategy failure.
z Open fuses.
z A/C clutch relay.
z Shorted blend door actuator.
z Powertrain control module.
z Circuitry short/open.
z A/C cycling switch damaged.
z A/C system discharged/low
charge.
z Function selector switch
damaged.
z A/C pressure cut-off switch
damaged.
z A/C compressor clutch
damaged. z
Go To Pinpoint
Test C .
z The A/C is always on zCircuitry short/open.
z A/C cycling switch.
z A/C heater function selector
switch.
z Constant control relay
module.
z Incorrect A/C clutch air gap. z
Go To Pinpoint
Test D .
z Insufficient A/C cooling zRestricted A/C evaporator
core orifice.
z Low refrigerant level. z
Go To Pinpoint
Test E .
z No operation in all the
temperature settings z
Damaged blend door actuator
cable.
z Damaged air temperature
control door. z
Go To Pinpoint
Test F .
z The blower motor does
not operate z
Open fuse.
z Circuitry open/shorted.
z Damaged heater blower
motor switch (18578).
z Damaged heater blower
motor switch resistor (18591).
z Damaged blower motor relay.
z Damaged blower motor. z
Go To Pinpoint
Test G .
z The blower motor
operates continuously in z
Circuitry short/open.
z Damaged heater blower z
Go To Pinpoint Klj . 6 ba
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