AC system FORD MUSTANG 2003 Workshop Manual

COOL (blue) to WARM (red) causes a corresponding movement on the air temperature control
door and determines the temperature that the system will maintain.
z The A/C heater function selector switch combines a vacuum selector valve for direct control of
the vacuum control motors and electrical input to the instrument control module.
Control System Outputs
Blower Motor Switch Resistor
The heater blower motor switch resistor has the following features:
zThe assembly is located on the passenger side of the plenum assembly behind the glove
compartment (06010).
z Three resistance elements are mounted on the resistor board to provide four A/C blower motor
speeds.
z Depending on the heater blower motor switch position, series resistance is added or bypassed
in the A/C blower motor circuit to decrease or increase A/C blower motor speed.
z An overheating protective device (thermal limiter) will open the resistor coil circuit when the
temperature reaches 105°- 110°C (221°-230°F), interrupting the blower motor operation in all
speeds except HI.
z The thermal limiter cannot be reset and is not serviceable.
Control Actuators
Temperature Control Cable
The temperature control cable (19988) has the following features:
zThe cable assembly has a constant tension (pull- pull) dual cable design.
z The pull- pull design allows for constant smooth communication between the temperature control
knob and the air temperature blend door.
z The control cable can only be installed as an assembly.
Vacuum Control Motors
The vacuum control motors (18A318) control the position of the doors directing the air flow to the
different outlets. There are two types of vacuum control motors used in this system:
zSingle- diaphragm for air inlet and windshield defroster door operations.
z Double- diaphragm for air damper door operations.
Single- diaphragm motors have two positions:
z Shaft extended with no vacuum applied.
z Shaft retracted with vacuum applied.
Double- diaphragm motors have three positions:
z Shaft extended with no vacuum applied to either port.
z Shaft halfway retracted with vacuum applied to only one port. Klj . 3 ba
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DESCRIPTION AND OPERATION
Instrument Cluster and Panel Illumination
The instrument cluster and panel illumination system illuminates the following components:
zinstrument cluster (10849)
z audio unit (18806)
z A/C- heater control
z fog lamp switch
z transmission range indicator
z traction control switch
z rear window defrost control switch
The instrument cluster is a hybrid electronic cluster (HEC), which uses both hardwired circuitry and the
standard corporate protocol (SCP) communication network to transmit and receive information. The
Mustang instrument cluster backlighting has illumination bulbs that are installed separately from the
instrument cluster. The Cobra instrument cluster has a laminated, electroluminescent applique to
backlight the cluster . The electroluminescent applique and instrument cluster must be installed as an
assembly. SECTION 413-
00: Instrument Cluster and Panel Illumination 2003 Mustang Workshop Manual Klj . 1 ba
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Pinpoint Tests
PINPOINT TEST A: THE CONTROL ILLUMINATION IS INOPERATIVE
PINPOINT TEST B: THE INSTRUMENT CLUSTER ILLUMINATION IS
INOPERATIVE z
Bulb(s).
z The climate control
illumination is inoperative z
Circuitry.
z Bulb(s). z
Go To Pinpoint Test C .
z The audio system
illumination is inoperative z
Circuitry.
z Audio unit. z
Go To Pinpoint Test D .
z A single illumination source
is inoperative z
Circuitry.
z Switch. z
Go To Pinpoint Test E .
Test Step Result / Action to Take
A1 CHECK PARKING LAMPS
z
Place the headlamp switch in the ON
position.
z Are the exterior lamps on? Yes
Place the headlamp switch in the OFF position.
GO to
A2 .
No
REFER to Section 417 - 01 .
A2 CHECK HEADLAMP SWITCH
z
Key in OFF position.
z Carry out the headlamp switch
components test;
Refer to Wiring Diagrams Cell 149 for
schematic and connector information.
.
z Is the headlamp switch OK? Yes
RECONNECT the headlamp switch. GO to
A3 .
No
INSTALL a new headlamp switch. REFER to
Section 417 - 01 . TEST the system for normal
operation. A3 CHECK CIRCUIT 1045 (DB/WH)
z
Place the headlamp switch in the ON
position.
z Rotate the instrument panel dimmer
switch to the full illumination position.
z Measure voltage between central
junction box (CJB) fuse 37 (5A) and
ground.
z Is the voltage greater than 10 volts? Yes
REPAIR circuit 19 (LB/RD). TEST the system for
normal operation.
No
REPAIR circuit 1045 (DB/WH). TEST the system
for normal operation.
Test Step Result / Action to Take
B1 CHECK VOLTAGE TO INSTRUMENT CLUSTER
ILLUMINATION z
Disconnect: Instrument Cluster .
z Place the headlamp switch in the ON position.
z Rotate the instrument panel dimmer switch to the full Yes
GO to
B2 . Klj . 2 ba
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PINPOINT TEST C: THE CLIMATE CONTROL ILLUMINATION IS
INOPERATIVE illumination position.
z Measure the voltage between the instrument cluster C220b
pin 4, circuit 19 (LB/RD), harness side and ground.
z Is the voltage greater than 10 volts? No
REPAIR the circuit. TEST
the system for normal
operation.
B2 CHECK GROUND TO INSTRUMENT CLUSTER
z
Place the headlamp switch in the OFF position.
z Measure the resistance between the instrument cluster
C220b pin 1, circuit 1205 (BK), harness side and ground.
z Are the resistances less than 5 ohms? Yes
INSTALL a new instrument
cluster. REFER to
Section 413 - 01 . TEST the system
for normal operation.
No
REPAIR the circuit. TEST
the system for normal
operation. Test Step Result / Action to Take
C1 CHECK VOLTAGE TO CLIMATE CONTROL ILLUMINATION
z
Disconnect: Function Selector Switch C294b .
z Place the headlamp switch in the ON position.
z Rotate the instrument panel dimmer switch to the full
illumination position.
z Measure the voltage between the function selector switch
C294b pin 2, circuit 19 (LB/RD), harness side and ground.
z Is the voltage greater than 10 volts? Yes
GO to
C2 .
No
REPAIR the circuit.
TEST the system for
normal operation. C2 CHECK GROUND TO CLIMATE CONTROL Klj . 3 ba
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PINPOINT TEST D: THE AUDIO SYSTEM ILLUMINATION IS
INOPERATIVE z
Measure the resistance between the function selector switch
C294b pin 1, circuit 1205 (BK), harness side and ground.
z Is the resistance less than 5 ohms? Yes
INSTALL new
illumination bulb(s).
REFER to
Section 412 -
04 .
No
REPAIR the circuit.
TEST the system for
normal operation. Test Step Result / Action to Take
D1 CHECK VOLTAGE TO AUDIO UNIT
z
Disconnect: Audio Unit C290a.
z Place the headlamp switch in the ON position.
z Rotate the instrument panel dimmer switch to the full
illumination position.
z Measure the voltage between the audio unit C290a pin
1, circuit 19 (LB/RD), harness side and ground.
z Is the voltage greater than 10 volts? Yes
GO to
D2 .
No
REPAIR the circuit. TEST the
system for normal operation. D2 CHECK GROUND TO AUDIO UNIT
z
Measure the resistance between the audio unit C290a
pin 2, circuit 1205 (BK), harness side and ground.
z Is the resistance less than 5 ohms? Yes
REMOVE the audio unit and
SEND it to an authorized Ford
audio systems repair facility.
TEST the system for normal
operation.
No
REPAIR the circuit. TEST the
system for normal operation. Klj . 4 ba
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PINPOINT TEST E: A SINGLE ILLUMINATION SOURCE IS
INOPERATIVE
Test Step Result / Action to Take
E1 CHECK VOLTAGE TO THE SINGLE
ILLUMINATION SOURCE z
Disconnect: Inoperative Illumination Source.
z Place the headlamp switch in the ON position.
z Rotate the instrument panel dimmer switch to the
full illumination position.
z Measure the voltage between the inoperative
illumination source, circuit 19 (LB/RD), harness
side and ground.
z Is the voltage greater than 10 volts? Yes
GO to
E2 .
No
REPAIR the circuit. TEST the system
for normal operation. E2 CHECK SINGLE ILLUMINATION SOURCE
GROUND z
Measure the resistance between inoperative
illumination source, circuit 1205 (BK), harness side
and ground.
z Is the resistance less than 5 ohms? Yes
INSTALL a new component in
question. TEST the system for normal
operation.
No
REPAIR the circuit. TEST the system
for normal operation. Klj . 5 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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Instrument Cluster—
Cobra 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
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 — Boost gauge
10 — Oil pressure gauge
11 — CHECK FUEL CAP indicator
12 — BRAKE warning indicator Klj . 3 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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