fuse box diagram FORD MUSTANG 2003 Workshop Manual

DIAGNOSIS AND TESTING
Steering Column Switches
Refer to Wiring Diagrams Cell
13 , Power Distribution for schematic and connector information.
Refer to Wiring Diagrams Cell 81 , Interval Wiper/Washer for schematic and connector information.
Refer to Wiring Diagrams Cell 85 , Headlamps for schematic and connector information.
Refer to Wiring Diagrams Cell 90 , Turn/Stop/Hazard Lamps for schematic and connector information.
Inspection and Verification 1. Verify the customer concern by operating the multifunction or ignition switch.
2. Visually inspect for obvious signs of mechanical and electrical damage.
3. 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 scan tool does not communicate with the vehicle:
zcheck that the program card is correctly installed.
SECTION 211-
05: Steering Column Switches 2003 Mustang Workshop Manual Special Tool(s)
Worldwide Diagnostic System
(WDS)
418-
F224,
New Generation STAR (NGS)
Tester
418- F052, or equivalent scan
tool 73 Digital Multimeter
105-
R0051 or equivalent
Visual Inspection Chart Mechanical Electrical
z
Ignition key
z Ignition switch
z Multifunction switch
z Turn signal switch
z Hazard/flasher switch z
Battery junction box (BJB) Fuses:
„(3) IGN (40A)
z Central junction box (CJB) Fuses:
„6 (25A)
„ 39 (5A)
z Damaged wiring harness
z Loose or corroded connections Klj . 1 ba
82003 Mustang Workshop Manual
17. 11. 2011file:///C:/Ford/2000 - 2004/tsocache/SHEF_4464/S3B~us~en~ ...

DIAGNOSIS AND TESTING
Starting System
Refer to Wiring Diagrams Cell
20 , Starting System for schematic and connector information.
Inspection and Verification WARNING: When servicing starter motor or carrying out other underhood work in the
vicinity of the starter motor, be aware that the heavy gauge battery input lead at the starter
solenoid is "electrically hot" at all times. A protective cap or boot is provided over this terminal
that must be installed after servicing. Be sure to disconnect the battery negative cable before
servicing the starter. Failure to follow these instructions may result in personal injury.
WARNING: When working in area of the starter motor, be careful to avoid touching hot
exhaust components. Failure to follow these instructions may result in personal injury.
WARNING: When using a remote starter switch or jumper wire, be sure the ignition switch
is in the OFF position and the transmission is in PARK (A/T) or Neutral (M/T) with the parking
brake control fully applied.
1. Verify the customers concern by operating the starting system to duplicate the conditions.
2. Inspect to determine if any of the following mechanical or electrical concerns apply.
3. If the inspection reveals an obvious concern that can be readily identified, repair as necessary.
4. If the concern remains after the inspection, determine the symptom. GO to Symptom Chart .
SECTION 303-
06: Starting System 2003 Mustang Workshop Manual Special Tool(s)
Digital Multimeter
105-
R0051 or equivalent Visual Inspection Chart
Mechanical Electrical
z
Starter motor
z Brackets z
Battery
z Battery junction box (BJB) fuse ignition switch (40A)
z Central junction box (CJB) Fuse 6 (20A)
z Fuse 24 (10A)
z Damaged wiring harness
z Starter Relay
z Loose or corroded connections Klj . 1 ba
112003 Mustang Workshop Manual
18. 11. 2011file:///C:/Ford/2000 - 2004/tsocache/SHEF_4464/S3B~us~en~ ...

z
Measure the voltage between the central junction box fuse 6,
circuit 33 (WH/PK) and ground while holding the key in the
START position.
z Is the voltage greater than 10 volts? system for normal
operation.
No
GO to
B8 .
B8 CHECK CIRCUIT 1050 (LG/VT) FOR VOLTAGE
z
Key in OFF position.
z Disconnect: Ignition Switch C209.
z Key in ON position.
z Measure the voltage between the ignition switch connector
C209 pin B4, circuit 1050 (LG/VT) and ground.
z Is the voltage greater than 10 volts? Yes
GO to
B9 .
No
REPAIR circuit 1050
(LG/VT). TEST the
system for normal
operation. B9 CHECK THE IGNITION SWITCH
z
Carry out the ignition switch component test. Refer to
Refer to Wiring Diagrams Cell 149 for schematic and connector
information.
.
z Does the ignition switch test good? Yes
REPAIR circuit 33
(WH/PK). TEST the
system for normal
operation.
No
INSTALL a new ignition
switch. TEST the
system for normal
operation.
B10 CHECK CIRCUIT 1205 (BK) FOR OPEN
z
Key in OFF position. Yes
INSTALL a new starter
motor relay. TEST the
system for normal
operation.
No
REPAIR circuit 1205
(BK). TEST the system
for normal operation. Klj . 6 ba
112003 Mustang Workshop Manual
18. 11. 2011file:///C:/Ford/2000 - 2004/tsocache/SHEF_4464/S3B~us~en~ ...

DIAGNOSIS AND TESTING
External Controls
Refer to Wiring Diagrams Cell
37 , Shift Lock for schematic and connector information.
Refer to Wiring Diagrams Cell 29 , Transmission Control for schematic and connector information.
Inspection and Verification 1. Verify the customer concern by operating the transmission external control.
2. Visually inspect for obvious signs of mechanical and electrical damage; refer to the following chart:
3. If the concern is not visually evident, determine the symptom. GO to Symptom Chart .
Symptom Chart SECTION 307-
05: Automatic Transaxle/Transmission External Controls 2003 Mustang Workshop Manual Special Tool(s)
73 Digital Multimeter
105-
R0051 or equivalent
Visual Inspection Chart Mechanical Electrical
z
Shift control linkage binding.
z Shift lock actuator.
z Shift control cable.
z Interlock cable. z
Circuitry.
z Central junction box (CJB) fuse:
„17 (15A)
„ 28 (15A)
„ 35 (15A)
z Brake pedal position (BPP) switch.
z Wiring harness.
z Loose or corroded connections.
z Bulb.
SYMPTOM CHART Condition
Possible Sources Action
z The shift interlock
system does not
release/lock correctly z
Circuitry.
z CJB Fuse 17 (15A)
or Fuse 35 (15A).
z Shift lock actuator.
z Brake pedal position
(BPP) switch. z
Go To Pinpoint Test A . Klj . 1 ba
62003 Mustang Workshop Manual
18. 11. 2011file:///C:/Ford/2000 - 2004/tsocache/SHEF_2748/S3B~us~en~ ...

z
speed control actuator switches.
z brake pedal position (BPP) switch.
z clutch pedal position (CPP) switch.
z deactivator switch.
The output of the speed control servo is the:
zspeed control actuator cable controlling the throttle position.
Inspection and Verification
NOTE: If any concerns are noted with the speedometer, stoplamps, or horn, address those concerns
by referring to their associated sections before continuing speed control diagnosis.
1. Verify the customer concern by operating the speed control system.
2. Visually inspect for obvious signs of mechanical and electrical damage.
3. If the fault is not visually evident, verify the symptom and GO to the Symptom chart.
Symptom Chart
NOTE: New speed control diagnostic software is available in Version 12 or higher for the diagnostic
tool. When using this software, it is necessary to use Next Generation Speed Control Adapter 007-
00586 with the diagnostic tool.
NOTE: Refer to the Wiring Diagrams for connector numbers stated in the Pinpoint Test.
Visual Inspection Chart Mechanical Electrical
z
Deactivator switch
z Speed control actuator cable not attached to throttle
z Speed control actuator cable not fully seated to the
engine bracket z
Central junction box (CJB)
Fuse:
„15 (15A)
„ 33 (15A)
„ 35 (15A)
z Battery junction box (BJB)
fuse:
„HORN (20A)
z Wiring harness
z Loose or corroded
connections
z Speed control actuator
switches
Symptom Chart Condition
Possible Sources Action
z The speed control is zCentral junction zGo To Pinpoint Test A . Klj . 2 ba
132003 Mustang Workshop Manual
18. 11. 2011file:///C:/Ford/2000 - 2004/tsocache/SHEF_2308/S3B~us~en~ ...

DIAGNOSIS AND TESTING
Instrument Cluster and Panel Illumination
Refer to Wiring Diagrams Cell
71 , Instrument Illumination for schematic and connector information.
Inspection and Verification
NOTE: A new instrument cluster must be reconfigured. Refer to Section 418 - 01 .
NOTE: The instrument panel dimmer switch is a part of the headlamp switch.
1. Verify the customer concern.
2. Visually inspect for obvious signs of electrical damage.
3. If the fault is not visually evident, determine the symptom and proceed to the Symptom Chart.
Symptom Chart SECTION 413-
00: Instrument Cluster and Panel Illumination 2003 Mustang Workshop Manual Special Tool(s)
73III Automotive Meter
105-
R0057 or equivalent
Visual Inspection Chart Electrical
z
Central junction box (CJB) fuses:
„5 (15A)
„ 21 (5A)
„ 34 (20A)
„ 37 (5A)
„ 32 (15A)
„ 27 (20A)
z Circuitry
z Damaged switch
Symptom Chart Condition
Possible Sources Action
z The control illumination is
inoperative z
Central junction box
(CJB) fuse 37 (5A).
z Circuitry.
z Headlamp switch. z
Go To Pinpoint Test A .
z The instrument cluster
illumination is inoperative z
Circuitry.
z Instrument cluster. z
Go To Pinpoint Test B . Klj . 1 ba
52003 Mustang Workshop Manual
18. 11. 2011file:///C:/Ford/2000 - 2004/tsocache/SHEF_5108/S3B~us~en~ ...

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
52003 Mustang Workshop Manual
18. 11. 2011file:///C:/Ford/2000 - 2004/tsocache/SHEF_5108/S3B~us~en~ ...

DIAGNOSIS AND TESTING
Horn
Refer to Wiring Diagrams Cell
44 , Horns/Cigar Lighter for schematic and connector information.
Inspection and Verification 1. Verify the customer concern by operating the horn (13832).
2. Visually inspect for obvious signs of mechanical and electrical damage.
3. If fault is not visually evident, determine the symptom and proceed to Symptom Chart.
Symptom Chart SECTION 413-
06: Horn 2003 Mustang Workshop Manual Special Tool(s)
73 Digital Multimeter or
equivalent
105-
R0051
Visual Inspection Chart Mechanical Electrical
z
Damaged horns
z Damaged horn switch
z Damaged air bag sliding contact
(14A664) z
Blown battery junction box (BJB) Fuse Horn
Relay (20A)
z Damaged wiring harness
z Damaged connections
z Damaged horn relay
z Damaged horn switch
Symptom Chart Condition
Possible Sources Action
z The horn does not
sound z
BJB Fuse Horn Relay (20A).
z Circuitry.
z Horn relay.
z Air bag sliding contact.
z Horn switch.
z Horns. z
GO to
Pinpoint Test A .
z The horn sounds
continuously z
Circuitry.
z Horn relay.
z Remote entry system (generic
electronic module [GEM]) z
GO to
Pinpoint Test B . Klj . 1 ba
52003 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~ ...