Ford Galaxy / Ford S-MAX. Manual — part 702

Pinpoint Tests

The horn is always on

Horn relay.
BJB.
Horn switch.
Circuit(s).
Clockspring.

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REFER to the Ford diagnostic equipment.

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PINPOINT TEST A : THE HORN IS INOPERATIVE

TEST CONDITIONS

DETAILS/RESULTS/ACTIONS

A1: CHECK POWER TO THE HORN

Disconnect Horn C1RH02.

1

Measure the voltage between the horn C1RH02 pin
2, circuit GBB31B (BU/OG), harness side and

ground while pressing the horn switch.

2

Is the voltage greater than 10 volts?
Yes

GO to A2

.

No

GO to A3

.

A2: CHECK GROUND TO THE HORN

Measure the resistance between the horn C1RH02
pin 1, circuit GD312G (BK/VT), harness side and

ground.

1

Is the resistance less than 5 ohms?
Yes

INSTALL a new horn. TEST the system for normal
operation.

No

REPAIR circuit GD312G (BK/VT). TEST the system
for normal operation.

A3: CHECK POWER TO THE HORN RELAY

Disconnect Horn Relay R9.

1

Measure the voltage between the horn relay R9 pin
1, harness side and ground; and horn relay R9 pin

3, harness side and ground.

2

Are the voltages greater than 10 volts?

Yes

GO to A4

.

No

INSTALL a new BJB. TEST the system for normal
operation.

A4: CHECK HORN SWITCH CIRCUIT FOR OPEN

Measure the resistance between the horn relay R9
pin 2, circuit CRH04A (VT/GN), harness side and

ground while pressing the horn switch.

1

Is the resistance less than 5 ohms?
Yes

INSTALL a new horn Relay R9. Test the system for
normal operation.

No

GO to A5

.

A5: CHECK SUPPLY TO THE CJB

Disconnect CJB 1BB01.

1

Measure the voltage between the CJB 1BB01 pin 1,
harness side and ground and between the CJB

1BB01 pin 2, harness side and ground.

2

Are the voltages greater than 10 volts?
Yes

REPAIR the circuit SBB17. TEST the system for
normal operation.

No

GO to A6

.

A6: CHECK CIRCUIT CRH04A (BN) FOR OPEN

Measure the resistance between the CJB 1BB01 pin
46 component side and ground while pressing the

horn switch.

1

Is the resistance less than 5 ohms?
Yes

REPAIR the circuit CRH04A. TEST the system for
normal operation.

No

GO to A7

.

A7: CHECK CJB 1BB01 FOR OPEN

Measure the resistance between the CJB 1BB01 pin
13, harness side and ground while pressing the

1

horn switch.

Is the resistance less than 5 ohms?
Yes

INSTALL a new CJB 1BB01. Test the system for
normal operation.

No

GO to A8

.

A8: CHECK CIRCUIT CRH03A (BN) FOR OPEN

WARNING: To deactivate the driver air bag, refer to the procedure in section 501-

20B. Failure to follow this instruction, may result in personal injury.

Disconnect steering wheel module 2R115.

1

Measure the resistance between the steering wheel
module 2R115 pin 4, circuit CRH03-A (BN), harness

side and horn relay R9 pin 2, CRH03-A (BN),
harness side.

2

Is the resistance less than 5 ohms?
Yes

GO to A9

.

No

REPAIR the circuit CRH03-A. TEST the system for
normal operation.

A9: CHECK CIRCUIT GD133CJ (BK) FOR OPEN

Measure the resistance between the steering wheel
module 2R115 pin 7, circuit GD133CJ (BK), harness

side and ground.

1

Is the resistance less than 5 ohms?
Yes

GO to A10

.

No

REPAIR the circuit GD133CJ. TEST the system for
normal operation.

A10: CHECK CIRCUIT C2RH02AB FOR OPEN

Disconnect horn switch 2RH03.

1

Measure the resistance between the steering wheel
module 2R115 pin 7, circuit CRH02AB, harness side

and horn switch 2RH03 pin 1, circuit C2RH02B,
harness side.

2

Is the resistance less than 5 ohms?
Yes

GO to A11

.

No

REPAIR the circuit C2RH02AB. TEST the system for
normal operation.

A11: CHECK THE HORN SWITCH

Measure the resistance between the horn switch
2RH03 pin 1, component side and horn switch

2RH03 pin 2, component side while pressing the
horn switch.

1

Is the resistance less than 5 ohms?
Yes

GO to A12

.

No

INSTALL a new horn switch 2RH03. TEST the
system for normal operation.

A12: CHECK CIRCUIT C2RH03AB FOR OPEN

Measure the resistance between the steering wheel
module pin 4, circuit CRH03AB, harness side and

horn switch C2RH03 pin 2, circuit C2RH03AB,
harness side.

1

Is the resistance less than 5 ohms?
Yes

INSTALL a new steering wheel module. TEST the
system for normal operation.

No

REPAIR the circuit C2RH03AB. TEST the system for
normal operation.