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Horn - Vehicles Built From: 05-1999 > < 413-06 Horn|Horn

Mondeo 1997 Horn Diagnostic and Testing Guide - Built Up To 05-1999

Horn - Horn—Vehicles Built Up To: 05/1999 Mondeo 1997 (08/1996-09/2000)
Diagnosis and Testing

Refer to Wiring Diagrams Section 413-06, for schematic and connector information.

Inspection and Verification

  1. Verify the customer concern.
  1. Visually inspect for obvious signs of mechanical or electrical damage.

Visual Inspection Chart

Mechanical Electrical
  • Horn(s)
  • Fuse(s)
  • Wiring harness
  • Electrical connector(s)
  1. If an obvious cause for an observed or reported concern is found, correct the cause (if possible) before proceeding to the next step.
  1. If the concern is not visually evident, verify the symptom and refer to the Symptom Chart.

Symptom Chart

Symptom Possible Sources Action
The horn sounds continuously
*
Circuit(s).
*
Horn relay.
*
Horn switch.
*
GO to Pinpoint Test ??. .
The horn does not sound
*
Fuse(s).
*
Circuit(s).
*
Horn relay.
*
Horn switch.
*
Horn(s).
*
GO to Pinpoint Test ??. .

Pinpoint Tests

PINPOINT TEST A : THE HORN SOUNDS CONTINUOUSLY
TEST CONDITIONS DETAILS/RESULTS/ACTIONS
A1: CHECK CIRCUIT 29S-ME6 (OG/YE) FOR SHORT TO (B+)
1
Disconnect Horn Relay C69.

Does the horn stop when the relay is disconnected?
Yes
GO to A2. .
No
REPAIR the circuit. TEST the system for normal operation.
A2: CHECK CIRCUIT 31S-ME7 (BK/BU) FOR SHORT TO GROUND

1
Measure the resistance between the horn relay C69 pin 1, circuit 31S-ME7 (BK/BU), harness side and ground.

Is the resistance greater than 10,000 ohms?
Yes
INSTALL a new horn relay. TEST the system for normal operation.
No
GO to A3. .
A3: CHECK STEERING WHEEL HORN SWITCH
WARNING:
WARNING:Deactivate the air bag before proceeding. Refer to section 501-20B for the correct air bag deactivation procedure.
1
Remove the airbag. REFER to Section  501-20A Safety Belt System / 501-20B Supplemental Restraint System.
2
Disconnect Clockspring C896.

3
Measure the resistance between the clockspring C896 pin 1 and pin 2.

Is the resistance less than 5 ohms with the horn switch in the ON position and greater than 10,000 ohms with the horn switch in the OFF position?
Yes
GO to A4. .
No
REPAIR circuit 31S-ME7. TEST the system for normal operation.
A4: CHECK STEERING WHEEL HORN SWITCH
1
Disconnect Horn Switch.

2
Measure the resistance between the horn switch pin B and C.

Is the resistance greater than 10,000 ohms?
Yes
INSTALL a new clockspring. REFER to Section  501-20A Safety Belt System / 501-20B Supplemental Restraint System. TEST the system for normal operation.
No
INSTALL a new horn switch.
REFER to Horn Switch in this section.
TEST the system for normal operation.

PINPOINT TEST B : THE HORN DOES NOT SOUND
TEST CONDITIONS DETAILS/RESULTS/ACTIONS
B1: CHECK THE HORN RELAY
1
Disconnect Horn Relay C69.
2
Carry out the horn relay Component Test. Refer to the Wiring Diagrams.

Is the relay OK?
Yes
GO to B2. GO to Pinpoint Test B. .
No
INSTALL a new horn relay. TEST the system for normal operation.
B2: CHECK POWER TO THE HORN RELAY

1
Measure the voltage between horn relay C69 pin 2, harness side and ground, and between horn relay C69 pin 3, harness side and ground.

Are the voltages greater than 10 volts?
Yes
GO to B3. GO to Pinpoint Test B. .
No
If fuse F12 is OK, REPAIR the power feed to the horn relay. If fuse F12 has failed, Install a new fuse. TEST the system for normal operation. If the fuse fails again, REPAIR the power feed to the horn relay.
B3: CHECK THE HORN CIRCUIT

1
Measure the resistance between horn relay C69 pin 5, circuit 29S-ME6 (OG/YE), harness side and ground.

Is the resistance between 0.5 and 4 ohms?
Yes
GO to B4. GO to Pinpoint Test B. .
No
REPAIR circuit 29S-ME6. TEST the system for normal operation.
B4: CHECK POWER TO HORN SWITCH
WARNING:
WARNING:To deactivate the air bag, refer to the procedure in section 501-20B for the correct air bag deactivation procedure.
1
Remove the airbag. REFER to Section  501-20A Safety Belt System / 501-20B Supplemental Restraint System.
2
Remove the steering column lower shroud.
3
Disconnect Clockspring C896.

4
Measure the voltage between the clockspring C896 pin 2, circuit 31S-ME7 (BK/BU), harness side and ground.

Is the voltage greater than 10 volts?
Yes
GO to B5. GO to Pinpoint Test B. .
No
REPAIR circuit 31S-ME7. TEST the system for normal operation.
B5: CHECK THE HORN SWITCH GROUND CIRCUIT

1
Measure the resistance between clockspring C896 pin 1, circuit 31-ME7/PG13 (BK), harness side and ground.

Is the resistance less than 5 ohms?
Yes
GO to B6. GO to Pinpoint Test B. .
No
If equipped with speed control. GO to B7. GO to Pinpoint Test B. . Otherwise, REPAIR the circuit. TEST the system for normal operation.
B6: CHECK THE HORN SWITCH
1
Disconnect Horn Switch.

2
Measure the resistance between the horn switch pin B and C. Take note of the reading with the switch pressed as well as with the switch released.

Is the resistance greater than 10,000 ohms with the switch released and less than 5 ohms with the switch pressed?
Yes
INSTALL a new clockspring. REFER to Section  501-20A Safety Belt System / 501-20B Supplemental Restraint System. TEST the system for normal operation.
No
INSTALL a new horn switch.
REFER to Horn Switch in this section.
TEST the system for normal operation.
B7: CHECK SPEED CONTROL MODULE GROUND
1
Disconnect Speed Control Module C833.

2
Measure the resistance between the speed control module C833 pin 10, circuit 91-PG12 (BK/WH), harness side and ground.

Is the resistance less than 5 ohms?
Yes
REPAIR circuit 31-PG13. TEST the system for normal operation.
No
REPAIR circuit 91-PG12. TEST the system for normal operation.

Horn - Vehicles Built From: 05-1999 > < 413-06 Horn|Horn