Pinpoint Test A: The Horn Is Inoperative
Horn
Pinpoint Test A: The Horn Is Inoperative
Refer to Wiring Diagram Set 44, Horn/Cigar Lighter for schematic and connector information. Diagrams By Number
Normal Operation
The Battery Junction Box (BJB) supplies the switched and control voltage to the horn relay (part of the Smart Junction Box (SJB)) through circuit SBB02 (YE/RD). When the horn switches (part of the steering wheel) are pressed, the horn relay is grounded through the horn switch circuitry, energizing the horn relay. The horn relay then sends voltage to the horn through circuit CBP05 (YE), sounding the horn. Ground for the horn is supplied through circuit GD123 (BK/GY).
This pinpoint test is intended to diagnose the following:
- Fuse
- Wiring, terminals or connectors
- Steering wheel harness
- Horn
- Clockspring
- Horn switches (part of the steering wheel)
- SJB
PINPOINT TEST A: THE HORN IS INOPERATIVE
NOTICE: Use the correct probe adapter(s) when making measurements. Failure to use the correct probe adapter(s) may damage the connector.
NOTE: Failure to disconnect the battery when instructed will result in false resistance readings. Refer to Battery.
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A1 CHECK THE HORN OPERATION USING THE PANIC BUTTON
- Press the PANIC button on the Remote Keyless Entry (RKE) transmitter.
- Does the horn sound when the PANIC button is pressed?
Yes
GO to A2.
No
GO to A9.
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A2 CHECK CIRCUIT CRH02 FOR VOLTAGE
- Measure the voltage between the clockspring C218a-8, circuit CRH02 (BU/WH), harness side and ground.
- Is the voltage greater than 10 volts?
Yes
GO to A3.
No
GO to A4.
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A3 CHECK CIRCUIT GD116 (BK/VT) FOR AN OPEN
- Disconnect: Negative Battery Cable.
- Disconnect: Clockspring C218a.
- Measure the resistance between the clockspring C218a-7, circuit GD116 (BK/VT), harness side and ground.
- Is the resistance less than 5 ohms?
Yes
GO to A5.
No
REPAIR the circuit. TEST the system for normal operation.
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A4 CHECK CIRCUIT CRH02 (BU/WH) FOR AN OPEN
- Ignition OFF.
- Disconnect: SJB C2280b.
- Measure the resistance between the SJB C2280b-6, circuit CRH02 (BU/WH), harness side and the clockspring C218a-8, circuit CRH02 (BU/WH), harness side.
- Is the resistance less than 5 ohms?
Yes
GO to A12.
No
REPAIR the circuit. TEST the system for normal operation.
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A5 CHECK CIRCUIT GD165 (BK) FOR AN OPEN
- Depower the Supplemental Restraint System (SRS). Refer to Air Bag Systems.
- Disconnect: Clockspring C218b.
- Measure the resistance between the clockspring C218b-2, circuit GD165 (BK), harness side and a metal point on the steering wheel.
- Is the resistance less than 5 ohms?
Yes
GO to A6.
No
REPAIR the circuit. TEST the system for normal operation.
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A6 CHECK THE STEERING WHEEL HARNESS FOR AN OPEN
- Disconnect: Horn Switch C2296 and C2297.
- Measure the resistance between the clockspring C218b-1, circuit CRH02 (BU/WH), harness side and the horn switch C2296-1, circuit CRH02 (BU/WH), harness side; and between the clockspring C218b-1, circuit CRH02 (BU/WH), harness side and the horn switch C2297-1, circuit CRH02 (BU/WH), harness side.
- Are the resistances less than 5 ohms?
Yes
GO to A7.
No
REPAIR the circuit in question. INSTALL the driver air bag module. REFER to Air Bag Systems. TEST the system for normal operation.
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A7 CHECK THE CLOCKSPRING FOR AN OPEN
- Remove the driver air bag module. Refer to Air Bag Systems.
- Measure the resistance between the clockspring C218a pin 7, component side and the clockspring C218b pin 2, component side.
- Measure the resistance between the clockspring C218a pin 8, component side and the clockspring C218b pin 1, component side.
- Are the resistances less than 5 ohms?
Yes
GO to A8.
No
INSTALL a new clockspring. INSTALL the driver air bag module. REFER to Air Bag Systems. TEST the system for normal operation.
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A8 CHECK THE STEERING WHEEL HARNESS FOR OPENS
- Inspect the steering wheel harness for opens.
- Is the steering wheel harness OK?
Yes
INSTALL a new steering wheel. CLEAR the DTCs. REPEAT the self-test.
No
REPAIR or INSTALL a new steering wheel harness. INSTALL the driver air bag module. TEST the system for normal operation.
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A9 CHECK CIRCUIT CBP05 (YE) FOR VOLTAGE
- Disconnect: Horn C131.
- While pressing the horn switch, measure the voltage between the horn C131-2, circuit CBP05 (YE), harness side and the horn C131-1, circuit GD123 (BK/GY), harness side.
- Is the voltage greater than 10 volts?
Yes
INSTALL a new horn. REFER to Horn Service and Repair. TEST the system for normal operation.
No
VERIFY the SJB fuse 2 (20A) is OK. If OK, GO to A10. If not OK, REFER to the Wiring Diagrams to identify the possible causes of the circuit short.
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A10 CHECK CIRCUIT GD123 (BK/GY) FOR AN OPEN
- Disconnect: Negative Battery Cable.
- Disconnect: Horn C131.
- Measure the resistance between the horn C131-1, circuit GD123 (BK/GY), harness side and ground.
- Is the resistance less than 5 ohms?
Yes
GO to A11.
No
REPAIR the circuit. TEST the system for normal operation.
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A11 CHECK CIRCUIT CBP05 (YE) FOR AN OPEN
- Disconnect: SJB C2280a.
- Measure the resistance between the SJB C2280a-20, circuit CBP05 (YE), harness side and the horn C131-2, circuit CBP05 (YE), harness side.
- Is the resistance less than 5 ohms?
Yes
GO to A12.
No
REPAIR the circuit. TEST the system for normal operation.
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A12 CHECK FOR CORRECT SJB OPERATION
- Disconnect all the SJB connectors.
- Check for:
- corrosion
- damaged pins
- pushed-out pins
- Connect all the SJB connectors and make sure they seat correctly.
- Operate the system and verify the concern is still present.
- Is the concern still present?
Yes
INSTALL a new SJB. REFER to Body Control Systems. TEST the system for normal operation.
No
The system is operating correctly at this time. The concern may have been caused by a loose or corroded connector.
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