Ford Mustang (1999-2004) Service Manual: Horn (Diagnosis and Testing)
Refer to Wiring Diagrams Cell 44 , Horns/Cigar Lighter for schematic and connector information.
Special Tool(s)
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73 Digital Multimeter or equivalent 105-R0051 |
Inspection and Verification
1. Verify the customer concern by operating the horn (13832).
2. Visually inspect for obvious signs of mechanical and electrical damage.
Visual Inspection Chart
Mechanical | Electrical |
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3. If fault is not visually evident, determine the symptom and proceed to Symptom Chart.
Symptom Chart
Condition | Possible Sources | Action |
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Pinpoint Tests
PINPOINT TEST A: THE HORN DOES NOT SOUND
Test Step | Result / Action to Take |
A1 CHECK POWER SUPPLY TO HORN RELAY | Yes GO to A2 . No REPAIR the circuit in question. TEST the system for normal operation. |
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A2 CHECK HORN RELAY | Yes GO to A3 . No INSTALL a new horn relay. TEST the system for normal operation. |
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A3 CHECK HORN SWITCH SIGNAL TO HORN RELAY | Yes GO to A4 . No GO to A5 . |
Horn Switch Position
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A4 CHECK WIRE BETWEEN HORN RELAY AND HORN | Yes INSTALL new horns. TEST the system for normal operation. No REPAIR the circuit. TEST the system for normal operation. |
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A5 CHECK WIRE BETWEEN HORN RELAY AND AIR BAG SLIDING CONTACT | Yes GO to A6 . No REPAIR the circuit. TEST the system for normal operation. |
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A6 CHECK AIR BAG SLIDING CONTACT | Yes GO to A7 . No INSTALL a new air bag sliding contact. REFER to Section. TEST the system for normal operation. |
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A7 CHECK THE STEERING WHEEL SWITCH HARNESS | 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. |
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PINPOINT TEST B: THE HORN SOUNDS CONTINUOUSLY
Test Step | Result / Action to Take |
B1 CHECK HORN CIRCUIT 1 (DB) | Yes REPAIR Circuit 1 (DB) for short to battery. TEST the system for normal operation. No GO to B2 . |
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B2 CHECK HORN RELAY | Yes REINSTALL the horn relay. GO to B3 . No INSTALL a new horn relay. TEST the system for normal operation. |
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B3 CHECK CIRCUIT 6 (YE/LG) | Yes GO to B4 . No RECONNECT the air bag sliding contact. GO to B5 . |
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B4 CHECK GEM INPUT | Yes REPAIR Circuit 6 (YE/LG). TEST the system for normal operation. No INSTALL a new GEM; REFER to Section. TEST the system for normal operation. |
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B5 CHECK THE AIR BAG SLIDING CONTACT | Yes INSTALL a new air bag sliding contact. REFER to Section. TEST the system for normal operation. No GO to B6 . |
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B6 CHECK STEERING WHEEL SWITCH HARNESS | 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. |
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Horn
Torque Specifications
Horn
The horn system consists of the following:
dual horns (one high-pitched, one low-pitched)
horn switch (located underneath the driver side air bag module
[043 ...
Switch - Horn
Removal
1. Remove the driver side air bag module (043B13). Refer to Section.
2. Remove the switches.
1. Disconnect the horn wire from the switches.
2. Remove the horn switch screws and ...
Other materials:
Removal
1. Drain the engine cooling system.
2. Remove the air cleaner outlet tube.
3. Disconnect the fuel line.
4. Disconnect the upper radiator hose from the water outlet connector.
5. Disconnect and remove the upper radiator hose.
6. Disconnect the acce ...
Torque Converter Leak Check
Special Tool(s)
Leak Tester, Torque Converter
307-421
1. Clean the outside surface of the torque converter.
2. Install the special tool into the converter hub.
3. WARNING: Always follow correct safety procedures while using press.
Failure t ...
Driveline Angle
Item
Description
1
Bottom of the frame
2
Engine crankshaft centerline
3
Engine angle
4
Driveshaft and coupling shaft centerline
5
Driveshaft and coupling shaft angle
6
Rear axle pinion centerline ...