Horn System Ford Explorer Sport Trac II

TORQUE SPECIFICATIONS

TORQUE SPECIFICATIONS

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

The horn system consists of the following components

1. Horn switch (part of the steering wheel)
2. Clockspring
3. Horn relay (part of the SJB)
4. Horn
5. SJB

For removal and installation of the driver air bag module, refer to SUPPLEMENTAL RESTRAINT SYSTEM article.

Horn Location

The horn is mounted behind the LH front fender splash shield on the inner side of the fender well.

For removal and installation of the front fender splash shield, refer to FRONT END BODY PANELS article.

Special Tools Illustration Tool Name Tool Number 73III Automotive Meter 105-R0057 or equivalent Vehicle Communication Module (VCM) and Integrated Diagnostic System (IDS) software with appropriate hardware, or equivalent scan tool Flex Probe Kit 105-R025C or equivalent

Scheme 1

Scheme 2

Principles of Operation

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

The battery junction box (BJB) supplies voltage to the horn relay (part of the smart junction box [SJB]). When the horn switch (part of the steering wheel) is pressed, ground is supplied to the SJB through the clockspring. The SJB then energizes the horn relay, sending voltage to the horn, enabling the horn to sound.

The SJB provides a momentary ground to the horn relay as a configuration confirmation for the auto-locks and for the tire pressure monitoring system (TPMS) sensor training. The SJB also provides a momentary ground to the horn relay when the anti-theft system is armed, and an on then off ground when an intrusion is detected or the panic button is pressed on the remote keyless entry (RKE) key fob.

Inspection and Verification

1. Verify the customer concern.
2. Visually inspect for obvious signs of mechanical or electrical damage. VISUAL INSPECTION CHART Mechanical Electrical Horn Horn switch (part of the steering wheel) Battery junction box (BJB) fuse 2 (50A) Smart junction box (SJB) fuse 14 (20A) Wiring, terminals or connectors Clockspring BJB SJB
3. If an obvious cause for an observed or reported concern is found, correct the cause (if possible) before proceeding to the next step.
4. If the cause is not visually evident, connect the scan tool to the data link connector (DLC).
5. If the scan tool does not communicate with the VCM: Check the VCM connection to the vehicle. Check the scan tool connection to the VCM. Refer to «MODULE COMMUNICATIONS NETWORK»(/ford/explorer-sport-trac/ii-2006-2010/remont/communication-devices/#module-communications-network) article, No Power To The Scan Tool, to diagnose no communication with the scan tool.
6. If the scan tool does not communicate with the vehicle: Verify the ignition key is in the ON position. Verify the scan tool operation with a known good vehicle. Refer to «MODULE COMMUNICATIONS NETWORK»(/ford/explorer-sport-trac/ii-2006-2010/remont/communication-devices/#module-communications-network) article to diagnose no response from the PCM.
7. Carry out the network test. If the scan tool responds with no communication with the SJB, refer to «MODULE COMMUNICATIONS NETWORK»(/ford/explorer-sport-trac/ii-2006-2010/remont/communication-devices/#module-communications-network) article. If the network test passes, retrieve and record the continuous memory DTCs.
8. Clear the continuous DTCs and carry out the self-test diagnostics for the SJB.
9. If the DTCs retrieved are related to the concern, go to DTC Charts. For all other DTCs, refer to «MULTIFUNCTION ELECTRONIC MODULES»(/ford/explorer-sport-trac/ii-2006-2010/remont/communication-devices/#multifunction-electronic-modules) article.
10. If no DTCs related to the concern are retrieved, go to «Symptom Chart»(/ford/explorer-sport-trac/ii-2006-2010/remont/horns/#horn-system) .

DTC Charts

SMART JUNCTION BOX (SJB) DTC CHART

Symptom Chart

Symptom Chart

Pinpoint Test A: The Horn Is Inoperative

Refer to appropriate SYSTEM WIRING DIAGRAMS article, Horn/Cigar Lighter for schematic and connector information.

Normal Operation

The battery junction box (BJB) supplies voltage to the horn relay (part of the smart junction box [SJB]) through circuit SBB02 (YE/RD). When the horn switch (part of the steering wheel) is pressed, the switch closes and ground is applied from the steering wheel switch harness through the clockspring to the horn relay through circuit CRH02 (BU/WH). The horn relay is then energized, applying voltage to the horn through circuit CBP14 (VT/OG), enabling the horn to sound. Ground for the horn is supplied through circuit GD120 (BK/GN).

1. DTC B1217 (Horn Relay Coil Circuit Failure) - is a continuous and on-demand DTC that sets when the SJB detects an open on the horn relay output circuit.

This pinpoint test is intended to diagnose the following

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

Scheme 3

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Scheme 5

Scheme 6

Scheme 7

1. A1 CHECK THE SJB OUTPUT Key in ON position. Enter the following diagnostic mode on the diagnostic tool: SJB DataLogger Select the SJB PID (HORNRLY). Active command the horn on and then off. Does the horn sound when commanded on? YES : Go to A2 . NO : Go to A5 .
2. A2 CHECK CIRCUIT CRH02 (BU/WH) FOR AN OPEN Depower the supplemental restraint system (SRS). Refer to «SUPPLEMENTAL RESTRAINT SYSTEM»(/ford/explorer-sport-trac/ii-2006-2010/remont/airbag/#supplemental-inflatable-restraint-system) article. Disconnect: SJB C2280c Disconnect: Clockspring C218a Measure the resistance between the clockspring C218a-8, circuit CRH02 (BU/WH), harness side and the SJB C2280c-6, circuit CRH02 (BU/WH), harness side. Is the resistance less than 5 ohms? YES : Go to A3 . NO : REPAIR the circuit. REPOWER the SRS. REFER to «SUPPLEMENTAL RESTRAINT SYSTEM»(/ford/explorer-sport-trac/ii-2006-2010/remont/airbag/#supplemental-inflatable-restraint-system) article. CLEAR the DTCs. REPEAT the self-test.
3. A3 CHECK THE CLOCKSPRING FOR AN OPEN Remove the driver air bag module. Refer to «SUPPLEMENTAL RESTRAINT SYSTEM»(/ford/explorer-sport-trac/ii-2006-2010/remont/airbag/#supplemental-inflatable-restraint-system) article. Disconnect: Upper Clockspring Connector Measure the resistance between the clockspring C218a pin 8, component side and the upper clockspring C218b pin 1, component side. Is the resistance less than 5 ohms? YES : Go to A4 . NO : INSTALL a new clockspring. INSTALL the driver air bag module and REPOWER the SRS. REFER to «SUPPLEMENTAL RESTRAINT SYSTEM»(/ford/explorer-sport-trac/ii-2006-2010/remont/airbag/#supplemental-inflatable-restraint-system) article. CLEAR the DTCs. REPEAT the self-test.
4. A4 CHECK THE STEERING WHEEL SWITCH HARNESS FOR DAMAGE OR OPENS Inspect the steering wheel switch harness for damage or opens. Is the steering wheel switch harness OK? YES : INSTALL a new steering wheel. REFER to «STEERING COLUMN»(/ford/explorer-sport-trac/ii-2006-2010/remont/steering-column/#steering-column) article. CLEAR the DTCs. REPEAT the self-test. NO : REPAIR or INSTALL a new steering wheel switch harness. CLEAR the DTCs. REPEAT the self-test.
5. A5 CHECK CIRCUIT GD120 (BK/GN) FOR AN OPEN Key in OFF position. Disconnect: Horn C1101 Measure the resistance between the horn C1101-1, circuit GD120 (BK/GN), harness side and ground. Is the resistance less than 5 ohms? YES : Go to A6 . NO : REPAIR the circuit. CLEAR the DTCs. REPEAT the self-test.
6. A6 CHECK CIRCUIT CBP14 (VT/OG) FOR VOLTAGE Connect: SJB C2280e Measure the voltage between the horn C1101-2, circuit CBP14 (VT/OG), harness side, and the horn C1101-1, circuit GD120 (BK/GN), harness side, while pressing the horn switch. Is the voltage greater than 10 volts? YES : INSTALL a new horn. REFER to «Horn»(/ford/explorer-sport-trac/ii-2006-2010/remont/horns/#horn-system) . CLEAR the DTCs. REPEAT the self-test. NO : VERIFY the SJB fuse 14 (20A) is OK. If OK, go to A7 .
7. A7 CHECK CIRCUIT CBP14 (VT/OG) FOR AN OPEN Measure the resistance between the SJB C2280e-17, circuit CBP14 (VT/OG), harness side, and the horn C1101-2, circuit CBP14 (VT/OG), harness side. Is the resistance less than 5 ohms? YES : Go to A8 . NO : REPAIR the circuit. CLEAR the DTCs. REPEAT the self-test.
8. A8 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»(/ford/explorer-sport-trac/ii-2006-2010/remont/communication-devices/#multifunction-electronic-modules) 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.

Pinpoint Test B: The Horn Is Always On

Refer to appropriate SYSTEM WIRING DIAGRAMS article, Horn/Cigar Lighter for schematic and connector information.

The battery junction box (BJB) supplies voltage to the horn relay (part of the smart junction box [SJB]) through circuit SBB02 (YE/RD). When the horn switch (part of the steering wheel) is pressed, the switch closes and ground is applied from the steering wheel switch harness through the clockspring to the horn relay through circuit CRH02 (BU/WH). The horn relay is then energized, applying voltage to the horn through circuit CBP14 (VT/OG), enabling the horn to sound.

1. DTC B1218 (Horn Relay Coil Circuit Short to Vbatt) - is a continuous and on-demand DTC that sets when the SJB detects a short to voltage on the horn relay coil circuit.

This pinpoint test is intended to diagnose the following

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

Scheme 8

Scheme 9

1. B1 CHECK CIRCUIT CBP14 (VT/OG) FOR A SHORT TO VOLTAGE Key in OFF position. Disconnect: SJB C2280e Does the horn continue to sound? YES : REPAIR the circuit. CLEAR the DTCs. REPEAT the self-test. NO : Go to B2 .
2. B2 CHECK THE HORN SWITCH INPUT Connect: SJB C2280e Disconnect: Upper Clockspring Disconnect: SJB C2280c 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 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»(/ford/explorer-sport-trac/ii-2006-2010/remont/airbag/#supplemental-inflatable-restraint-system) article. CLEAR the DTCs. REPEAT the self-test.
4. B4 CHECK THE CLOCKSPRING FOR A SHORT TO GROUND Connect: Clockspring C218a Measure the resistance between the SJB C2280c-6, circuit CRH02 (BU/WH), harness side and ground. Is the resistance greater than 10,000 ohms? YES : Go to B6 . NO : INSTALL a new clockspring. INSTALL the driver air bag module. REFER to «SUPPLEMENTAL RESTRAINT SYSTEM»(/ford/explorer-sport-trac/ii-2006-2010/remont/airbag/#supplemental-inflatable-restraint-system) article. CLEAR the DTCs. REPEAT the self-test.
5. B5 CHECK THE STEERING WHEEL SWITCH HARNESS FOR DAMAGE OR SHORTS Inspect the steering wheel switch harness for damage or shorts. Is the steering wheel switch harness OK? YES : INSTALL a new steering wheel. REFER to «STEERING COLUMN»(/ford/explorer-sport-trac/ii-2006-2010/remont/steering-column/#steering-column) article. INSTALL the driver air bag module. REFER to «SUPPLEMENTAL RESTRAINT SYSTEM»(/ford/explorer-sport-trac/ii-2006-2010/remont/airbag/#supplemental-inflatable-restraint-system) article. CLEAR the DTCs. REPEAT the self-test. NO : REPAIR or INSTALL a new steering wheel switch harness. INSTALL the driver air bag module. REFER to «SUPPLEMENTAL RESTRAINT SYSTEM»(/ford/explorer-sport-trac/ii-2006-2010/remont/airbag/#supplemental-inflatable-restraint-system) article. CLEAR the DTCs. REPEAT the self-test.
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»(/ford/explorer-sport-trac/ii-2006-2010/remont/communication-devices/#multifunction-electronic-modules) 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.

Scheme 10

REMOVAL AND INSTALLATION

1. Remove the LH front fender splash shield. For additional information, refer to «FRONT END BODY PANELS»(/ford/explorer-sport-trac/ii-2006-2010/remont/exterior-body-panels/#body-panel-system-front-end-body-panels) article.
2. Disconnect the electrical connector.
3. Remove the nut and the horn. To install, tighten to 10 Nm (89 lb-in).
4. To install, reverse the removal procedure.

See also:
• SUPPLEMENTAL RESTRAINT SYSTEM
• FRONT END BODY PANELS
• MODULE COMMUNICATIONS NETWORK
• MULTIFUNCTION ELECTRONIC MODULES
• STEERING COLUMN
• Symptom Chart
• Pinpoint Test A
• Pinpoint Test B