ABS FORD MUSTANG 2003 Workshop Manual

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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GENERAL PROCEDURES
Heater Hose Coupling
Disconnect
CAUTION: Do not attempt to install a new bushing, spacer or O- rings in the heater hose
coupling; damage to the heater hose coupling can result. If the heater hose coupling is the
cause of a coolant leak, the affected heater hose must be replaced as an assembly.
1. WARNING: The engine must be off, fully cool and the cooling system fully
depressurized before attempting to disconnect any heater water hoses. Failure to comply
with this warning can result in serious injury or burns from hot liquid escaping out of the
engine cooling system.
Depressurize the engine cooling system.
2. Push the heater hose toward the tube to fully expose the locking tabs.
3. NOTE: When compressing the white coupling retainer with the special tool, the special tool
must be perpendicular to and on the highest point of the coupling.
NOTE: If the heater hose coupling is accessible, the retainer tabs can be compressed by hand
to disconnect the heater hose.
Push the special tool over the coupling retainer windows to compress the retainer locking tabs.
SECTION 412-
00: Climate Control System - General Information 2003 Mustang Workshop Manual Special Tool(s)
Remover, Heater Hose Inlet
Tube
412-
042 (T85T-18539- AH) Disconnect Tool, Heater Hose
412-
127
Material Item Specification
MERPOL®
—
ESE-
M99B144- B Klj . 1 ba
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4.
NOTE: A slight twisting motion while pulling on the heater water hose may be necessary to
assist in the removal.
Pull the heater hose away from the heater core tube.
5. Spread the retainer tabs apart and slide the retainer off the tube. zDiscard the retainer.
Connect 1. Clean the tubes and lubricate with coolant hose lubricant or plain water.
2. Install a new coupling retainer (18D434) into the heater hose coupling housing. Klj . 2 ba
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The suction accumulator (19C836) is mounted to the A/C accumulator bracket (19D606) to the right of
the vehicle centerline. The inlet tube of the suction accumulator attaches directly to the A/C evaporator
core outlet tube and the outlet tube attaches to the A/C manifold and tube.
After entering the inlet of the suction accumulator, the heavier oil-
laden refrigerant contacts an
internally mounted dome (which serves as an umbrella) and drips down onto the bottom of the
canister.
zA small diameter oil bleed hole, in the bottom of the vapor return tube, allows the accumulated
heavier liquid refrigerant and oil mixture to reenter the compressor suction line at a controlled
rate.
z 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.
z A fine mesh screened filter fits tightly around the bottom of the vapor return tube to filter out
refrigerant system contaminant particles.
z A desiccant bag is mounted inside the canister to absorb any moisture which may be in the
refrigerant system.
z A fitting located on the top of the suction accumulator is used to attach the A/C cycling switch. A
long- travel Schrader- type valve stem core is installed in the fitting so that the A/C cycling switch
can be removed without discharging the A/C system.
A/C Cycling Switch
The A/C cycling switch is mounted on a Schrader- type valve fitting on the top of the suction
accumulator.
zA valve depressor, located inside the threaded end of the A/C cycling switch, presses in on the
Schrader valve stem.
z This allows the suction pressure inside the suction accumulator to control the operation of the
A/C cycling switch.
z The electrical switch contacts open when the suction pressure drops. The contacts close when
the suction pressure rises. For specifications regarding operating pressure(s), refer to Section 412 - 00 .
z The A/C cycling switch will control the A/C evaporator core pressure at a point where the
plate/fin surface temperature will be maintained slightly above freezing.
z This prevents icing of the A/C evaporator core and blockage of air flow.
z It is not necessary to discharge the refrigerant system to remove the A/C cycling switch.
Dual- Function Pressure Switch (4.6L)
The dual- function pressure switch is used to interrupt A/C compressor operation in the event of high Klj . 7 ba
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All vehicles
8. Remove the nuts and disconnect the lines. zDiscard the O- ring seals.
Vehicles with 4WABS 9. Remove the hydraulic control unit upper bracket bolts.
10. Raise the vehicle.
11. Remove the hydraulic control unit lower bracket bolt and position the hydraulic control unit aside.
12. Lower the vehicle.
All vehicles 13. Remove the bolts and the radiator brackets. Klj . 3 ba
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DESCRIPTION AND OPERATION
Instrument Cluster
The instrument cluster (10849) consists of the following components:
Instrument Cluster—
Base 3.8L Engine
SECTION 413-
01: Instrument Cluster 2003 Mustang Workshop Manual Item Part
Number Description
1 — Fuel gauge
2 — Engine coolant temperature gauge
3 — Speedometer
4 — Turn signal/hazard indicator
5 — High beam indicator
6 — Tachometer
7 — Odometer
8 — Trip odometer reset button
9 — Voltmeter gauge
10 — Oil pressure gauge
11 — CHECK FUEL CAP indicator
12 — BRAKE warning indicator
13 — ABS warning indicator
14 — Traction control indicator
15 — Overdrive off (O/D OFF) indicator (automatic Klj . 1 ba
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Instrument Cluster—
Base 4.6L Engine transmission)
16 — LOW FUEL level indicator
17 — SERVICE ENGINE SOON indicator
18 — THEFT indicator
19 — AIR BAG warning indicator
20 — Charging system indicator
21 — Safety belt warning indicator
Item Part
Number Description
1 — Fuel gauge
2 — Engine coolant temperature gauge
3 — Speedometer
4 — Turn signal/hazard indicator
5 — High beam indicator
6 — Tachometer
7 — Odometer
8 — Trip odometer reset button
9 — Voltmeter gauge
10 — Oil pressure gauge
11 — CHECK FUEL CAP indicator
12 — BRAKE warning indicator
13 — ABS warning indicator Klj . 2 ba
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13 — ABS warning indicator
14 — Traction control indicator
15 — Overdrive off (O/D OFF) indicator (automatic
transmission)
16 — LOW FUEL level indicator
17 — SERVICE ENGINE SOON indicator
18 — THEFT indicator
19 — AIR BAG warning indicator
20 — Charging system indicator
21 — Safety belt warning indicator Klj . 4 ba
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DIAGNOSIS AND TESTING
Instrument Cluster
Refer to Wiring Diagrams Cell
60 , Instrument Cluster for schematic and connector information.
Principles of Operation
NOTE: A new instrument cluster must be reconfigured. Refer to Section 418 - 01 .
The instrument cluster is a hybrid electronic cluster (HEC). The instrument cluster uses both hardwired
and the standard corporate protocol (SCP) communication network to transmit and receive
information. As a technician it is very important to understand:
zwhere the input originates from.
z all information necessary in order for a feature to operate.
z which module(s) receive(s) the input or command message.
z does the module which received the input control the output of the feature, or does it output a
message over the SCP network to another module?
z which module controls the output of the feature.
The instrument cluster carries out a display prove- out to verify that the warning/indicator miniature
bulbs for monitored systems are functioning correctly. When the ignition switch is in the ON position
with the engine off, the following warning indicators will prove out:
zanti- lock brake (ABS) warning indicator
SECTION 413-
01: Instrument Cluster 2003 Mustang Workshop Manual Special Tool(s)
Worldwide Diagnostic System
(WDS)
418-
F224,
New Generation STAR (NGS)
Tester
418- F052, or equivalent
diagnostic tool Instrument Gauge System
Tester
014-
R1063 or equivalent 73III Automotive Meter
105-
R0057 or equivalent Klj . 1 ba
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The boost pressure gauge on the instrument cluster receives and measures the boost pressure
directly from the intake manifold. The boost pressure gauge will display between 0.0-
0.48 kpa (0.0-10
psi) boost pressure dependent upon accelerator position, engine load, and engine rpm.
LOW FUEL Level Indicator
The low fuel level indicator is hardwired from the fuel sender to the instrument cluster. The instrument
cluster will illuminate the low fuel indicator when the usable fuel quantity is less than 1/8 tank (15%) of
fuel tank capacity.
Oil Pressure Gauge
The oil pressure gauge is hardwired from the oil pressure switch to the instrument cluster. The oil
pressure gauge will indicate either normal or no oil pressure.
CHECK FUEL CAP
The CHECK FUEL CAP indicator is used to indicate significant leaks in the fuel tank evaporative
system due to a loose fuel cap. Fuel tank pressure is monitored by the PCM. If a leak is detected the
PCM signals a fault to the instrument cluster via the SCP network. Once the PCM has detected a
loose fuel cap and the CHECK FUEL CAP indicator is illuminated, the indicator will remain illuminated
until the fuel cap is secured and the vehicle has been running for several minutes. For additional
information, refer to the Powertrain Control/Emissions Diagnosis (PC/ED) manual.
BRAKE Warning Indicator
The BRAKE warning indicator activates when the generic electronic module (GEM) detects the ignition
switch circuits are in the RUN state, when the GEM detects low brake fluid level, or that the parking
brake is applied. The BRAKE warning indicator will prove out starting when the GEM detects that the
ignition circuits have made a transition to RUN or START from OFF, ACC, or keyout and ending when
either three seconds have elapsed or when the GEM detects the ignition circuits have made a
transition to OFF, ACC, or keyout.
Safety Belt Warning Indicator
The safety belt switch is hardwired to the GEM. The safety belt warning indicator will be illuminated
when the GEM sends a ground signal to the instrument cluster.
ABS Warning Indicator
The ABS warning indicator will be illuminated when the anti- lock brake control module sends a ground
signal to the instrument cluster. The prove- out of the ABS indicator is controlled by the anti- lock brake
control module.
SERVICE ENGINE SOON Indicator
The SERVICE ENGINE SOON indicator receives its signal from the PCM over the SCP network. If the
instrument cluster does not receive a message from the PCM within five seconds, the instrument
cluster will illuminate the SERVICE ENGINE SOON indicator and log a diagnostic trouble code (DTC).
High Beam Indicator
The high beam indicator will illuminate when the steering column multifunction switch is in the high
beam position by sending a battery signal to the instrument cluster. Right and Left Turn Indicator Klj . 3 ba
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