FORD MUSTANG 2003 Workshop Manual

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
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Pinpoint Tests
PINPOINT TEST A: THE HORN DOES NOT SOUND module.
z Horn switch. Test Step Result / Action to
Take A1 CHECK POWER SUPPLY TO HORN RELAY
z
Disconnect: Horn Relay.
z Measure the voltage between the horn relay connector Pin 2,
Circuit 460 (YE/LB), harness side and ground; and between the
horn relay connector Pin 5, Circuit 460 (YE/LB), harness side and
ground.
z Are the voltages greater than 10 volts? Yes
GO to
A2 .
No
REPAIR the circuit in
question. TEST the
system for normal
operation. A2 CHECK HORN RELAY
z
Check the horn relay; refer to Wiring Diagrams Cell 149.
z Is the horn relay OK? Yes
GO to
A3 .
No
INSTALL a new horn
relay. TEST the
system for normal
operation. A3 CHECK HORN SWITCH SIGNAL TO HORN RELAY
z
Measure the resistance between horn relay connector Pin 1,
Circuit 6 (YE/LG), harness side and ground under the following
conditions:
Horn Switch Position Horn Switch Position Resistance
Pressed Less than 5 ohms
Released Greater than 10,000 ohms Yes
GO to
A4 .
No
GO to A5 . Klj . 2 ba
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z
Are the resistances correct? A4 CHECK WIRE BETWEEN HORN RELAY AND HORN
z
Key in OFF position.
z Disconnect: Horn C1262.
z Disconnect: Horn C1261.
z Measure the resistance between the horn relay connector Pin 3,
Circuit 1 (DB), harness side and horn C1261 or horn C1256
harness side; and between the horn relay connector Pin 3, Circuit
1 (DB), harness side and ground.
z Is the resistance less than 5 ohms between the horn relay and
the horns, and greater than 10,000 ohms between the horn
relay and ground? Yes
INSTALL new horns.
TEST the system for
normal operation.
No
REPAIR the circuit.
TEST the system for
normal operation.
A5 CHECK WIRE BETWEEN HORN RELAY AND AIR BAG SLIDING
CONTACT z
Key in OFF position.
z Deactivate the air bag system; refer to Section 501 - 20B .
z Disconnect: Air Bag Sliding Contact C218a.
z Measure the resistance between air bag sliding contact C218a Pin
2, Circuit 6 (YE/LG), harness side and horn relay connector Pin 1,
Circuit 6 (YE/LG) harness side.
z Is the resistance less than 5 ohms? Yes
GO to
A6 .
No
REPAIR the circuit.
TEST the system for
normal operation. A6 CHECK AIR BAG SLIDING CONTACT
z
Disconnect the steering wheel switch harness from the air bag
sliding contact.
z Measure the resistance between upper air bag sliding contact Yes
GO to
A7 . Klj . 3 ba
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PINPOINT TEST B: THE HORN SOUNDS CONTINUOUSLY connector Pin 3, Circuit 6 (component side), and air bag sliding
contact C218a Pin 2, Circuit 6 (component side).
z Is the resistance less than 5 ohms? No
INSTALL a new air
bag sliding contact.
REFER to
Section 501 - 20B . TEST the
system for normal
operation. A7 CHECK THE STEERING WHEEL SWITCH HARNESS
z
Inspect the steering wheel switch harness for chafing, opens or
possible short to ground.
z Is the steering wheel switch harness OK? Yes
INSTALL a new horn
switch. REFER to
Switch
— Horn . TEST
the system for normal
operation.
No
INSTALL a new
steering wheel switch
harness. TEST the
system for normal
operation. Test Step Result / Action to Take
B1 CHECK HORN CIRCUIT 1 (DB)
z
Key in OFF position.
z Disconnect: Horn Relay.
z Does the horn continue to sound? Yes
REPAIR Circuit 1 (DB) for short to battery. TEST
the system for normal operation.
No
GO to
B2 .
B2 CHECK HORN RELAY
z
Check the horn relay; refer to Wiring
Diagrams Cell 149.
z Is the horn relay OK? Yes
REINSTALL the horn relay. GO to
B3 .
No
INSTALL a new horn relay. TEST the system for
normal operation. B3 CHECK CIRCUIT 6 (YE/LG)
z
Disconnect: Air Bag Sliding Contact
C218a .
z Does the horn continue to sound? Yes
GO to
B4 .
No
RECONNECT the air bag sliding contact. GO to
B5 .
B4 CHECK GEM INPUT
z
Disconnect: GEM C201e. Yes Klj . 4 ba
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z
Does the horn continue to sound? REPAIR Circuit 6 (YE/LG). TEST the system for
normal operation.
No
INSTALL a new GEM; REFER to
Section 419 - 10 .
TEST the system for normal operation. B5 CHECK THE AIR BAG SLIDING
CONTACT z
Deactivate the air bag system. Refer
to Section 501 - 20B .
z Disconnect the steering wheel switch
harness from the air bag sliding
contact.
z Does the horn continue to sound? Yes
INSTALL a new air bag sliding contact. REFER to
Section 501
- 20B . TEST the system for normal
operation.
No
GO to B6 .
B6 CHECK STEERING WHEEL SWITCH
HARNESS z
Inspect the steering wheel switch
harness for shorts, opens, or any
damage.
z Is the steering wheel switch
harness OK? Yes
INSTALL a new horn switch. REFER to
Switch —
Horn . TEST the system for normal operation.
No
INSTALL a new steering wheel switch harness.
TEST the system for normal operation. Klj . 5 ba
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REMOVAL AND INSTALLATION
Switch —
Horn
Removal 1. Remove the driver side air bag module (043B13). Refer to Section 501 - 20B .
2. Remove the switches. 1. Disconnect the horn wire from the switches.
2. Remove the horn switch screws and remove the switches.
Installation 1. To install, reverse the removal procedure. zProve out the air bag system. Refer to Section 501 - 20B .
SECTION 413-
06: Horn 2003 Mustang Workshop Manual Klj . 1 ba
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Klj . 2 ba
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DESCRIPTION AND OPERATION
Warning Devices
The warning device system consists of the following components:
zdoor ajar switches
z generic electronic module (GEM)
z key- in-ignition warning switch
z safety belt switch
z parklamp switch
SECTION 413-
09: Warning Devices 2003 Mustang Workshop Manual Klj . 1 ba
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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
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and when the GEM detects the headlamps or parklamps are on from the exterior lamp circuits. Refer
to the Chime Duration Table in this section for audible output, duration time, and priority ratings.
Safety Belt Warning Chime
The safety belt warning chime and safety belt warning lamp activate when the GEM detects the
ignition switch circuits are in the RUN or START state and when the GEM detects the safety belt is
unbuckled from the safety belt circuit. The safety belt warning lamp indicator will prove out for three
seconds whenever the GEM detects that the ignition circuits make a transition to RUN from OFF, ACC,
or KEYOUT state. Refer to the Chime Duration Table in this section for audible output, duration time,
and priority ratings.
Belt Minder
NOTE:
Belt minder is a configurable item. If configuring using a diagnostic tool, refer to Section 418 -
01 . To configure without using a diagnostic tool, refer to
Belt Minder Deactivating/Activating in this
section.
The belt minder feature supplements the current safety belt warning function. The belt minder feature
is enabled after the current safety belt warning is complete. If the driver safety belt is not buckled
approximately five seconds after the safety belt warning light has turned off, the belt minder reminds
the driver that their safety belt is unbuckled by intermittently sound a chime and illuminating the safety
belt warning lamp in the instrument cluster. While activated, the belt minder alternates the chime and
indicator from on for six seconds to off for 30 seconds.
The belt minder reminder stops when:
zthe drive seat belt is buckled.
z the ignition is turned to OFF or ACC.
z five minutes have elapsed since belt minder has started.
Inspection and Verification
NOTE: Upon installation of a new GEM, the module must be reconfigured. For additional information,
refer to Section 418 - 01 .
1. The warning lamps are a GEM controlled system; refer to Section 419 - 10 .
2. Verify the customer concern by operating the system in question.
3. Visually inspect for the following obvious signs of mechanical and electrical damage.
Chime Duration Table Feature Audible Output Duration Priority
Safety belt Chime, 60/minute 740 Hz 6.0 seconds 1
Key-
in-ignition Chime, 120/minute 740 Hz Continuous 2
Headlamps left on Chime, 240/minute 740 Hz Continuous 3
Airbag Single tone, 1,000 Hz Continuous 4
Door ajar Single tone, 1,000 Hz 1.0 second 7 Klj . 2 ba
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