Horn: Overview Ford Fusion I рестайлинг

Principles of Operation

Note. The smart junction box (SJB) is also known as the generic electronic module (GEM).

The battery junction box (BJB) supplies the control and switched voltage to the horn relay (part of the SJB). When the horn switches are pressed, ground is supplied through the clockspring to the horn relay. The horn relay is then energized, directing voltage to the horn. When the perimeter anti-theft system is armed, the SJB provides a momentary ground to the horn relay control side to indicate the system is armed, and an on and off ground when an intrusion is detected or the panic feature is activated.

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

1. Fuse
2. Wiring, terminals or connectors
3. Horn
4. Clockspring
5. Horn switches (part of the steering wheel)
6. SJB

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1. A1 CHECK THE HORN OPERATION USING THE PANIC BUTTON Press the PANIC button on the integrated key head transmitter (IKT). Does the horn sound when the PANIC button is pressed? YES : Go to A2 . NO : Go to A7 .
2. A2 CHECK CIRCUIT GD165 (BK) FOR AN OPEN Key in OFF position. Remove the driver air bag module. Refer to «SUPPLEMENTAL RESTRAINT SYSTEM»(ref-291881) article. Disconnect: Clockspring C218b Measure the resistance between the clockspring C218b-2, circuit GD165 (BK), harness side and ground. Is the resistance less than 5 ohms? YES : Go to A3 . NO : REPAIR the circuit. INSTALL the driver air bag module. REFER to «SUPPLEMENTAL RESTRAINT SYSTEM»(ref-291881) article. TEST the system for normal operation.
3. A3 CHECK CIRCUIT GD116 (BK/VT) FOR AN OPEN 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 A4 . NO : REPAIR the circuit. INSTALL the driver air bag module. REFER to «SUPPLEMENTAL RESTRAINT SYSTEM»(ref-291881) article. TEST the system for normal operation.
4. A4 CHECK CIRCUIT CRH02 (BU/WH) FOR AN OPEN 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 A5 . NO : REPAIR the circuit. INSTALL the driver air bag module. REFER to «SUPPLEMENTAL RESTRAINT SYSTEM»(ref-291881) article. TEST the system for normal operation.
5. A5 CHECK THE CLOCKSPRING FOR AN OPEN Measure the resistance between the clockspring C218a pin 7, component side and the clockspring C218b pin 2, component side; and 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 A6 . NO : INSTALL a new clockspring. REFER to «SUPPLEMENTAL RESTRAINT SYSTEM»(ref-291881) article. TEST the system for normal operation.
6. A6 CHECK THE STEERING WHEEL SWITCH 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 : INSTALL a new steering wheel. REFER to «STEERING COLUMN»(ref-291893) article. TEST the system for normal operation. NO : REPAIR the circuit in question. INSTALL the driver air bag module. REFER to «SUPPLEMENTAL RESTRAINT SYSTEM»(ref-291881) article. TEST the system for normal operation.
7. A7 CHECK CIRCUIT GD123 (BK/GY) FOR AN OPEN Key in OFF position. Disconnect: Horn C131 Measure the resistance between the horn C131-1, circuit GD123 (BK/GY), harness side and ground. Is the resistance less than 0.1 ohm? YES : Go to A8 . NO : REPAIR the circuit. TEST the system for normal operation.
8. A8 CHECK CIRCUIT CBP05 (YE) FOR VOLTAGE Measure the voltage between the horn C131-2, circuit CBP05 (YE), harness side, and the horn C131-1, circuit GD123 (BK/GY), harness side, while pressing the horn switch. Is the voltage greater than 10 volts? YES : INSTALL a new horn. REFER to «Horn»(ref-291895-S13857341892008073000000) . TEST the system for normal operation. NO : VERIFY the SJB fuse 2 (20A) is OK. If OK, go to A9 . If not OK, refer to the Wiring Diagrams Manual to identify the possible causes of the circuit short.
9. A9 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 0.1 ohm? YES : Go to A10 . NO : REPAIR the circuit. TEST the system for normal operation.
10. A10 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 «MULTIFUNCTION ELECTRONIC MODULES»(ref-291878) article. 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.

Refer to SYSTEM WIRING DIAGRAMS article for Fusion, SYSTEM WIRING DIAGRAMS article for Milan or SYSTEM WIRING DIAGRAMS article for MKZ, Horn/Cigar Lighter for schematic and connector information.

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

1. Wiring, terminals or connectors
2. Clockspring
3. Horn switches (part of the steering wheel)
4. SJB

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1. B1 CHECK CIRCUIT CBP05 (YE) FOR A SHORT TO VOLTAGE Key in OFF position. Disconnect: SJB C2280a Does the horn continue to sound? YES : REPAIR the circuit. TEST the system for normal operation. NO : Go to B2 .
2. B2 CHECK THE HORN SWITCH INPUT Connect: SJB C2280a Disconnect: SJB C2280b Does the horn continue to sound? YES : Go to B6 . NO : Go to B3 .
3. B3 CHECK CIRCUIT CRH02 (BU/WH) FOR A SHORT TO GROUND Depower the supplemental restraint system (SRS). Refer to «SUPPLEMENTAL RESTRAINT SYSTEM»(ref-291881) article. Disconnect: Clockspring C218a Measure the resistance between the clockspring C218a-8, circuit CRH02 (BU/WH), harness side and ground. Is the resistance greater than 10,000 ohms? YES : Go to B4 . NO : REPAIR the circuit. REPOWER the SRS. REFER to «SUPPLEMENTAL RESTRAINT SYSTEM»(ref-291881) article. TEST the system for normal operation.
4. B4 CHECK THE CLOCKSPRING FOR A SHORT TO GROUND Remove the driver air bag module. Refer to «SUPPLEMENTAL RESTRAINT SYSTEM»(ref-291881) article. Connect: Clockspring C218a Disconnect: Clockspring C218b Measure the resistance between the SJB C2280b-6, circuit CRH02 (BU/WH), harness side and ground. Is the resistance greater than 10,000 ohms? YES : Go to B5 . NO : INSTALL a new clockspring. INSTALL the driver air bag module. REFER to «SUPPLEMENTAL RESTRAINT SYSTEM»(ref-291881) article. TEST the system for normal operation.
5. B5 CHECK THE STEERING WHEEL SWITCH HARNESS FOR A SHORT TO GROUND Disconnect: Horn Switch C2296 and C2297 Measure the resistance between the clockspring 218b-1, circuit CRH02 (BU/WH), harness side and ground. Is the resistance greater than 10,000 ohms? YES : INSTALL a new steering wheel. REFER to «STEERING COLUMN»(ref-291893) article. INSTALL the driver air bag module. REFER to «SUPPLEMENTAL RESTRAINT SYSTEM»(ref-291881) article. TEST the system for normal operation. NO : REPAIR the circuit. INSTALL the driver air bag module. REFER to «SUPPLEMENTAL RESTRAINT SYSTEM»(ref-291881) article. TEST the system for normal operation.
6. B6 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 «MULTIFUNCTION ELECTRONIC MODULES»(ref-291878) article. 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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