2003 FORD MUSTANG diagram

DIAGNOSIS AND TESTING
Gauges And Warning Devices
Refer to Wiring Diagrams Cell
59 , Generic Electronic Module for schematic and connector
information.
Refer to Wiring Diagrams Cell 60 , Instrument Cluster for schematic and connector information.
Refer to Wiring Diagrams Cell 66 , Warning Chime for schematic and connector information.
Principles of Operation
Key- In-Ignition Warning Chime
The key- in-ignition warning chime activates when the generic electronic module (GEM) detects the
ignition switch circuits are in the OFF or ACC states and when the GEM detects the driver door is ajar
from the driver door ajar circuits. Refer to the Chime Duration Table in this section for audible output,
duration time, and priority ratings.
Airbag Warning Chime
The airbag warning chime activates when the GEM detects the ignition switch circuits are in the RUN
state and when the GEM detects a chime is requested from the airbag system circuit. Refer to the
Chime Duration Table for audible output, duration time, and priority ratings.
Door Ajar Warning Chime
The door ajar warning chime activates when the GEM detects the ignition switch circuits are in the
RUN state and when the GEM detects the driver or passenger door is ajar from the driver and
passenger door ajar circuits. Refer to the Chime Duration Table in this section for audible output,
duration time, and priority ratings.
Headlamps Left on Warning Chime
The headlamps left on warning chime activates when the GEM detects the ignition switch circuits are
in the KEYOUT state, when the GEM detects the driver door is ajar from the driver door ajar circuit, SECTION 413-
09: Warning Devices 2003 Mustang Workshop Manual Special Tool(s)
73III Automotive Meter
105-
R0057 or equivalent Worldwide Diagnostic System
(WDS)
418-
F224,
New Generation STAR (NGS)
Tester
418- F048, or equivalent
diagnostic tool Klj . 1 ba
202003 Mustang Workshop Manual
18. 11. 2011file:///C:/Ford/2000 - 2004/tsocache/SHEF_5108/S3B~us~en~ ...

DIAGNOSIS AND TESTING
Charging System
Refer to Wiring Diagrams Cell
12 , Charging System for schematic and connector information.
Principles of Operation SECTION 414-
00: Charging System — General Information 2003 Mustang Workshop Manual Special Tool(s)
73III Automotive Meter
105-
R0057 or equivalent SABRE Premium Battery and
Electrical System Tester
010-
00736 or equivalent Connector C102c End View
A Circuit 36 (YE/WH)
I Circuit 904 (LG/RD) Klj . 1 ba
142003 Mustang Workshop Manual
18. 11. 2011file:///C:/Ford/2000 - 2004/tsocache/SHEF_5108/S3B~us~en~ ...

8. If the draw is found to be excessive, pull fuses from the battery/central junction box one at a
time and note the current drop. Do not reinstall the fuses until you are finished testing.
9. Check the wiring schematic in the wiring diagram for any circuits that run from the battery without passing through the battery/central junction box. Disconnect these circuits if the draw is
still excessive.
Battery— Electronic Drains Which Shut Off When the Battery Cable is Disconnected
1. Repeat the steps of the battery drain testing.
2. Make sure all doors are closed and accessories are off. Without starting the engine, turn the ignition switch to RUN for a moment and then OFF. Wait a few minutes for the illuminated entry
lamps to turn off if equipped.
3. Connect the ammeter and read the amperage draw.
The current reading (current drain) should be less than 50 mA (0.05 amp). If the current drain exceeds
50 mA (0.05 amp) after a few minutes, and if this drain did not show in previous tests, the drain is most
likely caused by an inoperative electronic component. As in previous tests, remove the fuses from the
battery/central junction box one at a time to locate the problem circuit.
Generator On- Vehicle Tests
CAUTION: To prevent damage to the generator, do not make jumper wire connections
except as directed.
CAUTION: Do not allow any metal object to come in contact with the housing and the
internal diode cooling fins with key on or off. A short circuit will result and burn out the diodes.
NOTE: Battery posts and cable clamps must be clean and tight for accurate meter indications.
NOTE: Refer to the Battery Tester Procedure Manual for complete directions for testing the charging
system.
1. Turn off all lamps and electrical components.
2. Place the vehicle in transmission range NEUTRAL and apply the parking brake.
3. Carry out the Load Test and No- Load Test according to the following component tests:
Generator On- Vehicle Tests— Load Test
1. Switch the battery tester to the ammeter function.
2. Connect the positive and negative leads of the battery tester to the corresponding battery terminals.
3. Connect the current probe to the generator B+ output terminal, circuit 38 (BK/OG). Klj . 12 ba
142003 Mustang Workshop Manual
18. 11. 2011file:///C:/Ford/2000 - 2004/tsocache/SHEF_5108/S3B~us~en~ ...

DIAGNOSIS AND TESTING
Audio System
Refer to Wiring Diagrams Cell
130 , Radio for schematic and connector information.
Inspection and Verification 1. Verify the customer concern by operating the electronic audio system with the engine running.
2. Visually inspect the following for obvious signs of mechanical and electrical damage.
3. If the concern remains and the fault is not detected, proceed to the Symptom Chart to continue diagnostics.
Symptom Chart SECTION 415-
00: Entertainment System — General Information 2003 Mustang Workshop Manual Special Tool(s)
73III Automotive Meter
105-
R0057 or equivalent
Visual Inspection Chart Mechanical Electrical
z
Audio unit
z Antenna or antenna cable
z Speakers mounting/speaker cones
z Radio ignition interference capacitor, radio frequency
interference suppression bond or radio receiver hood bonding
strap cleanliness z
Battery junction box
(BJB) fuses:
„3 (40A)
„ 4 (40A)
„ 6 (40A)
z Central junction box
(CJB) fuses:
„6 (20A)
„ 27 (25A)
„ 32 (15A)
z Ignition switch
z Circuitry
z Audio unit
Symptom Chart Condition
Possible Sources Action
z The audio unit is
inoperative/does not operate z
Central
junction box z
Go To Pinpoint Test A . Klj . 1 ba
242003 Mustang Workshop Manual
18. 11. 2011file:///C:/Ford/2000 - 2004/tsocache/SHEF_5108/S3B~us~en~ ...

DIAGNOSIS AND TESTING
Headlamps
Refer to Wiring Diagrams Cell
85 , Headlamps for schematic and connector information.
Inspection and Verification 1. Verify the customer concern by operating the headlamps.
2. Visually inspect for the following obvious signs of mechanical and electrical damage.
3. If the concern is not visually evident, determine the symptom and proceed to Symptom Chart.
Symptom Chart SECTION 417-
01: Exterior Lighting 2003 Mustang Workshop Manual Special Tool(s)
73III Automotive Meter or
equivalent
105-
R0057
Visual Inspection Chart Mechanical Electrical
z
Damaged headlamp switch (11654)
z Damaged multifunction switch (13K359) z
Battery junction box (BJB) fuse 2 (30A)
z Central junction box (CJB) fuse(s):
„38 (20A)
„ 4 (7.5A) (RH)
„ 10 (7.5A) (LH)
z Damaged wiring harness
z Loose or corroded connections
z Headlamp bulb
Symptom Chart Condition
Possible Sources Action
z Both
headlamps are
inoperative z
Battery junction
box (BJB) fuse 2
(30A).
z Headlamp
switch.
z Circuitry.
z Multifunction
switch. z
Go To Pinpoint Test A .
z The low beams
are inoperative z
Circuitry.
z Multifunction
switch. z
Go To Pinpoint Test B . Klj . 1 ba
82003 Mustang Workshop Manual
18. 11. 2011file:///C:/Ford/2000 - 2004/tsocache/SHEF_5108/S3B~us~en~ ...

DIAGNOSIS AND TESTING
Stoplamps
Refer to Wiring Diagrams Cell
90 , Turn/Stop/Hazard Lamps for schematic and connector information.
Inspection and Verification 1. Verify the customer concerns.
2. Visually inspect for the following obvious signs of mechanical or electrical damage.
3. If an obvious cause for an observed or reported concern is found, correct the cause (if possible) before proceeding to the next step.
4. If the concern is not visually evident, determine the symptom and refer to the Symptom Chart.
Symptom Chart SECTION 417-
01: Exterior Lighting 2003 Mustang Workshop Manual Special Tool(s)
73III Automotive Meter or
equivalent
105-
R0057
Visual Inspection Chart Mechanical Electrical
z
Brake pedal position (BPP) switch z
Central junction box (CJB) fuse 41 (15A)
z Circuitry
z Bulb(s)
Symptom Chart Condition
Possible Sources Action
z The stoplamps are
inoperative z
Central junction box (CJB)
fuse 41 (15A).
z Circuitry.
z Brake pedal position
(BPP) switch. z
Go To Pinpoint Test G .
z One or more stoplamps
are inoperative z
Circuitry.
z Multifunction switch. z
Go To Pinpoint Test H .
z The stoplamps are on
continuously z
Brake pedal position
(BPP) switch.
z Multifunction switch. z
Go To Pinpoint Test I . Klj . 1 ba
52003 Mustang Workshop Manual
18. 11. 2011file:///C:/Ford/2000 - 2004/tsocache/SHEF_5108/S3B~us~en~ ...

DIAGNOSIS AND TESTING
Turn Signal and Hazard Lamps
Refer to Wiring Diagrams Cell
90 , Turn/Stop/Hazard Lamps for schematic and connector information.
Inspection and Verification 1. Verify the customer concern.
2. Visually inspect for the following obvious signs of mechanical and electrical damage.
3. If an obvious cause for an observed or reported concern is found, correct the cause (if possible) before proceeding to the next step.
4. If the cause is not visually evident, verify the symptom and refer to the Symptom Chart.
Symptom Chart SECTION 417-
01: Exterior Lighting 2003 Mustang Workshop Manual Special Tool(s)
73 III Automotive Meter
105-
R0057 or equivalent
Visual Inspection Chart Mechanical Electrical
z
Multifunction switch z
Central junction box (CJB) Fuse 13 (15A).
z CJB Fuse 18 (15A).
z Circuitry
z Electronic flasher
z Turn signal/hazard lamp
Symptom Chart Condition
Possible Sources Action
z The turn signal
lamps are never
on z
Central junction
box (CJB) fuse 13
(15A).
z CJB Fuse 18
(15A).
z Circuitry.
z Multifunction
switch. z
Go To Pinpoint Test J . Klj . 1 ba
42003 Mustang Workshop Manual
18. 11. 2011file:///C:/Ford/2000 - 2004/tsocache/SHEF_5108/S3B~us~en~ ...

PINPOINT TEST K: THE HAZARD FLASHER LAMPS ARE NEVER ON z
Disconnect: Multifunction Switch C202b.
z Measure the resistance between multifunction switch C202b Pin
44, Circuit 44 (LB), harness side and the electronic flasher C2141
Pin 1, Circuit 44 (LB), harness side; and between multifunction
switch C202b Pin 44, Circuit 44 (LB), harness side and ground.
z Is the resistance less than 5 ohms between the multifunction
switch and the electronic flasher, and greater than 10,000
ohms between the multifunction switch and ground? GO to
J3 .
No
REPAIR the circuit.
TEST the system for
normal operation. J3 CHECK THE CONTINUITY OF THE MULTIFUNCTION SWITCH
z
Carry out the multifunction switch component test.
Refer to Wiring Diagrams Cell 149 for schematic and connector
information.
z Is the switch OK? Yes
INSTALL a new
electronic flasher.
TEST the system for
normal operation.
No
INSTALL a new
multifunction switch.
REFER to
Section 211 - 05 . TEST the
system for normal
operation. Test Step Result / Action to
Take K1 CHECK THE VOLTAGE TO THE ELECTRONIC FLASHER
z
Disconnect: Electronic Flasher C2141.
z Measure the voltage between electronic flasher C2141 Pin 3,
Circuit 383 (RD/WH), harness side and ground.
z Is the voltage greater than 10 volts? Yes
GO to
K2 .
No
REPAIR the circuit.
TEST the system for
normal operation. K2 CHECK CIRCUIT 385 (WH/RD)
z
Disconnect: Multifunction Switch C202b. Yes Klj . 3 ba
42003 Mustang Workshop Manual
18. 11. 2011file:///C:/Ford/2000 - 2004/tsocache/SHEF_5108/S3B~us~en~ ...