2003 FORD MUSTANG relay

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
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Symptom Chart
Pinpoint Tests
PINPOINT TEST A: THE ENGINE DOES NOT CRANK AND THE
RELAY DOES CLICK
SYMPTOM CHART Condition
Possible Sources Action
z The engine does
not crank and the
relay does click z
Battery.
z Fuse.
z Starter
motor/solenoid.
z Ignition switch.
z Circuit. z
Go To Pinpoint Test A .
z The engine does
not crank and the
relay does not
click z
Fuse.
z Battery.
z Starter relay.
z Ignition switch.
z Digital transmission
range (TR) sensor.
z Starter solenoid.
z Clutch pedal
position (CPP)
switch.
z Circuit. z
Go To Pinpoint Test B .
z The engine
cranks slowly z
Battery.
z Starter
motor/solenoid.
z Circuit. z
Go To Pinpoint Test C .
z Unusual starter
noise z
Starter motor
mounting.
z Starter motor.
z Incorrect starter
drive engagement. z
Go To Pinpoint Test D .
z The starter spins
but the engine
does not crank z
Starter Motor zINSPECT the starter motor
mounting and engagement.
REPAIR as necessary.
z Damaged
flywheel/ring gear
teeth. z
INSPECT the flywheel/ring
gear for damaged, missing or
worn teeth. REPAIR as
necessary. Test Step Result / Action to Take
A1 CHECK THE VOLTAGE TO THE STARTER RELAY
z
Measure the voltage between the starter relay pin 30,
circuit 1050 (LG/VT) and ground. Yes
GO to
A2 .
No
REPAIR circuit 1050 (LG/VT) Klj . 2 ba
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z
Is the voltage greater than 12.5 volts? for an open. TEST the
system for normal operation.
A2 CHECK THE VOLTAGE TO THE STARTER MOTOR
SOLENOID z
Measure the voltage between the starter motor solenoid
positive terminal and ground.
z Is the voltage 12.5 volts or greater? Yes
GO to
A3 .
No
REPAIR circuit 2037 (RD) for
an open. TEST the system
for normal operation. A3 MANUALLY JUMP THE STARTER MOTOR
z
Connect one end of a fused (15A) jumper wire to the
positive terminal of the battery and touch the other end to
the starter solenoid S- terminal.
z Does the starter solenoid engage? Yes
GO to
A4 .
No
INSTALL a new starter
motor. REFER to Starter Motor — 3.8L or
Starter Motor — 4.6L . TEST the
system for normal operation. A4 TEST THE STARTER MOTOR RELAY
z
Carry out the relay component test on the starter motor
relay. Refer to the relay component test in this section.
z Does the starter motor relay test good? Yes
REPAIR circuit 33
(WH/PK)/262 (BN/PK) for an
open. TEST the system for
normal operation.
No
INSTALL a new starter motor
relay. TEST the system for
normal operation. Klj . 3 ba
112003 Mustang Workshop Manual
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PINPOINT TEST B: THE ENGINE DOES NOT CRANK AND THE
RELAY DOES NOT CLICK
Test Step Result / Action to Take
B1 CHECK CIRCUIT 33 (WH/PK) FOR VOLTAGE
z
Disconnect: Starter Motor Relay.
z Key in START position.
z Measure the voltage between the starter motor relay pin 85,
circuit 33 (WH/PK) and ground while holding the key in the
START position.
z Is the voltage greater than 10 volts? Yes
GO to
B10 .
No
For automatic
transmissions, GO to
B2 . For manual
transmissions, GO to
B5 .
B2 CHECK CIRCUIT 32 (RD/LB) FOR VOLTAGE AT THE DIGITAL
TR SENSOR z
Key in OFF position.
z Disconnect: Digital TR Sensor C110.
z Key in START position.
z Measure the voltage between the digital TR sensor C110 pin
10, circuit 32 (RD/LB) and ground while holding the key in the
START position.
z Is the voltage greater than 10 volts? Yes
GO to
B3 .
No
GO to B7 .
B3 CHECK CIRCUIT 33 (WH/PK) FOR OPEN
z
Key in OFF position.
z Measure the resistance between the digital TR sensor C110 pin Yes
GO to
B4 .
No
REPAIR circuit 33
(WH/PK). TEST the
system for normal
operation. Klj . 4 ba
112003 Mustang Workshop Manual
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12, circuit 33 (WH/PK) and the starter motor relay pin 86, circuit
33 (WH/PK).
z Is the resistance less than 5 ohms? B4 CHECK DIGITAL TRANSMISSION RANGE (TR) SENSOR
ADJUSTMENT z
Carry out the digital TR sensor adjustment. Refer to Section 307 - 01 .
z Is the digital TR sensor adjusted correctly? Yes
INSTALL a new digital
TR sensor. TEST the
system for normal
operation.
No
ADJUST the digital TR
as necessary. TEST the
system for normal
operation.
B5 CHECK CIRCUIT 32 (RD/LB) FOR VOLTAGE AT THE CLUTCH
SWITCH OR JUMPER z
Key in OFF position.
z Disconnect: Clutch Pedal Switch C255.
z Key in START position.
z Measure the voltage between the clutch pedal switch C255 pin
2, circuit 32 (RD/LB) and ground while holding the key in the
START position.
z Is the voltage greater than 10 volts? Yes
GO to
B6 .
No
GO to B7 .
B6 CHECK CIRCUIT 33 (WH/PK)/32 (RD/LB) FOR OPEN
z
Key in OFF position.
z Measure the resistance between the clutch pedal switch C255
pin 1, circuit 33 (WH/PK)/32 (RD/LB) and the starter motor relay
pin 86, circuit 33 (WH/PK)/32 (RD/LB).
z Is the resistance less than 5 ohms? Yes
INSTALL a new clutch
pedal switch. TEST the
system for normal
operation.
No
REPAIR circuit 33
(WH/PK)/32 (RD/LB).
TEST the system for
normal operation.
B7 CHECK FOR VOLTAGE AT FUSE 6
z
Key in OFF position.
z Disconnect: Fuse #6.
z Key in START position. Yes
REPAIR circuit 32
(RD/LB). TEST the Klj . 5 ba
112003 Mustang Workshop Manual
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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
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PINPOINT TEST C: THE ENGINE CRANKS SLOWLY
PINPOINT TEST D: UNUSUAL STARTER NOISE z
Measure the resistance between the starter motor relay pin 86,
circuit 1205 (BK) and ground.
z Is the resistance less than 5 ohms? Test Step Result / Action to Take
NOTE:
Before beginning this test, be sure that the battery is tested and fully charged. C1 CHECK THE VOLTAGE TO THE STARTER
z
Key in OFF position.
z Measure the voltage between the starter motor
solenoid positive terminal and ground.
z Is the voltage 12.5 volts or greater? Yes
GO to
C2 .
No
REPAIR the circuit between the
battery and the starter solenoid.
CLEAN and TIGHTEN the
connections at the battery terminals.
TEST the system for normal
operation. C2 CHECK MOTOR GROUND CIRCUIT
z
Carry out the Motor Ground Circuit test; refer to
Component Tests in this section.
z Is the ground OK? Yes
INSTALL a new starter motor.
REFER to
Starter Motor — 3.8L or
Starter Motor — 4.6L . TEST the
system for normal operation.
No
REPAIR the ground circuit as
necessary. TEST the system for
normal operation. Test Step Result / Action to Take
D1 CHECK THE STARTER MOTOR
MOUNTING z
Inspect the starter motor mounting Yes Klj . 7 ba
112003 Mustang Workshop Manual
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REMOVAL AND INSTALLATION
Relay Switch
1. Disconnect the battery ground cable. For additional information, refer to Section 414 - 01 .
2. Remove the power distribution box cover.
3. Remove the starter relay from the power distribution box.
Installation 1. To install, reverse the removal procedure.
SECTION 303-
06: Starting System 2003 Mustang Workshop Manual Klj . 1 ba
22003 Mustang Workshop Manual
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