DIAGNOSIS AND TESTING

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413-06-1 Horn 413-06-1 DIAGNOSIS AND TESTING Horn Special Tool(s) Fluke 77-IV Digital Multimeter FLU77-4 or equivalent Vehicle Communication Module (VCM) and Integrated Diagnostic System (IDS)

1 Horn DIAGNOSIS AND TESTING Horn Special Tool(s) Fluke 77-IV Digital Multimeter FLU77-4 or equivalent Vehicle Communication Module (VCM) and Integrated Diagnostic System (IDS) software with appropriate hardware, or equivalent scan tool Flex Probe Kit 300-NUD105-R025DE or equivalent Principles of Operation NOTE: The Smart Junction Box (SJB) is also known as the Generic Electronic Module (GEM). The SJB supplies the switched and control voltage to the horn relay (integrated into the SJB). When the horn switch (part of the driver air bag module) 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 when the anti-theft system is armed, and an on then off ground when the panic button is pressed on the Remote Keyless Entry (RKE) transmitter. Inspection and Verification 1. Verify the customer concern. 2. Visually inspect for obvious signs of mechanical or electrical damage. Visual Inspection Chart Horn Mechanical Electrical Smart Junction Box (SJB) fuse 24 (20A) Wiring, terminals or connectors SJB Symptom Chart Symptom Chart Condition Possible Sources Action The horn is inoperative Fuse GO to Pinpoint Test A. Wiring, terminals or connectors Steering wheel harness Horn Clockspring Horn switch (part of the driver air bag module) Smart Junction Box (SJB) The horn is always on Wiring, terminals or GO to Pinpoint Test B. connectors Steering wheel harness Clockspring Horn switch (part of the driver air bag module) SJB Copyright 2009, Ford Motor Company Last updated: 6/25/2009

2 Horn Pinpoint Tests Pinpoint Test A: The Horn Is Inoperative Refer to Wiring Diagrams Cell 44, Horn/Cigar Lighter for schematic and connector information. rmal Operation The Smart Junction Box (SJB) supplies the switched and control voltage to the horn relay (integrated into the SJB). When the horn switch (part of the driver air bag module) is pressed, ground is supplied to the horn relay, energizing the horn relay. The horn relay then provides voltage to the horn, enabling the horn to sound. This pinpoint test is intended to diagnose the following: Fuse Wiring, terminals or connectors Steering wheel harness Horn Clockspring Horn switch (part of the driver air bag module) SJB A1 A2 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. CHECK THE SJB OUTPUT Ignition ON. Enter the following diagnostic mode on the scan tool: SJB GO to A2. DataLogger. Select the SJB horn active command. Command the horn on VERIFY the SJB fuse 24 (20A) is OK. If and then off. OK, GO to A7. If not OK, REFER to the Does the horn sound when commanded on? Wiring Diagrams Manual to identify the possible causes of the circuit short. CHECK FOR VOLTAGE TO THE CLOCKSPRING Ignition OFF. Depower the Supplemental Restraint System (SRS). Refer to Section B. Disconnect: Clockspring C218a. Connect: Negative Battery Cable. Measure the voltage between the clockspring C218a-8, circuit SRH01 (YE/RD), harness side and ground. A3 GO to A4. Is the voltage greater than 10 volts? GO to A3. CHECK THE HORN RELAY COIL GROUND CIRCUIT FOR AN OPEN Disconnect: SJB C2280b.

3 Horn A3 PINPOINT TEST A: THE HORN IS INOPERATIVE CHECK THE HORN RELAY COIL GROUND CIRCUIT FOR AN OPEN Measure the resistance between the SJB C2280b-41, circuit SRH01 (YE/RD), harness side and the clockspring C218a-8, circuit SRH01 (YE/RD), harness side. A4 GO to A10. REPAIR circuit SRH01 (YE/RD) for an open. REPOWER the SRS. REFER to Section B. TEST the system for Is the resistance less than 5 ohms? normal operation. CHECK FOR VOLTAGE TO THE CLOCKSPRING USING THE CONNECTOR GROUND Measure the voltage between the clockspring C218a-8, circuit SRH01 (YE/RD), harness side and the clockspring C218a-5, circuit GD116 (BK/VT), harness side. A5 GO to A5. REPAIR circuit GD116 (BK/VT) for an open. REPOWER the SRS. REFER to Section B. TEST the system for Is the voltage greater than 10 volts? normal operation. CHECK THE CLOCKSPRING FOR AN OPEN Remove the driver air bag module. Refer to Section B. Disconnect: Upper Clockspring Connector.

4 Horn A5 PINPOINT TEST A: THE HORN IS INOPERATIVE CHECK THE CLOCKSPRING FOR AN OPEN Measure the resistance between the clockspring C218a pin 8, component side and the upper clockspring connector pin 7, component side. Measure the resistance between the clockspring C218a pin 5, component side and the upper clockspring connector pin 10, component side. A6 GO to A6. INSTALL a new clockspring. REFER to Section B. TEST the system for Is the resistance less than 5 ohms? normal operation. CHECK THE STEERING WHEEL HARNESS FOR OPENS Inspect the steering wheel harness for opens. Is the steering wheel harness OK? INSTALL a new driver air bag module. REFER to Section B. TEST the system for normal operation. REPAIR or INSTALL a new steering wheel harness. INSTALL the driver air bag module. REFER to Section B. TEST the system for normal operation.

5 Horn A7 PINPOINT TEST A: THE HORN IS INOPERATIVE CHECK FOR VOLTAGE TO THE HORN While pressing the horn switch, measure the voltage between the horn C131-2, circuit CRH02 (BU/WH), harness side and ground. A8 GO to A8. Is the voltage greater than 10 volts? GO to A9. CHECK FOR VOLTAGE TO THE HORN USING THE CONNECTOR GROUND While pressing the horn switch, measure the voltage between the horn C131-2, circuit CRH02 (BU/WH), harness side, and the horn C131-1, circuit GD124 (BK/VT), harness side. A9 INSTALL a new horn. REFER to Horn in this section. TEST the system for normal operation. REPAIR circuit GD124 (BK/VT) for an open. TEST the system for normal Is the voltage greater than 10 volts? operation. CHECK THE SJB HORN OUTPUT CIRCUIT FOR AN OPEN Disconnect: SJB C2280e. Measure the resistance between the SJB C2280e-5, circuit CRH02 (BU/WH), harness side, and the horn C131-2, circuit CRH02 (BU/WH), harness side. GO to A10. REPAIR circuit CRH02 (BU/WH) for an open. TEST the system for normal Is the resistance less than 5 ohms? operation.

6 Horn A10 PINPOINT TEST A: THE HORN IS INOPERATIVE CHECK FOR CORRECT SJB OPERATION Disconnect all the SJB connectors. Check for: INSTALL a new SJB. REFER to Section corrosion TEST the system for normal damaged pins operation. pushed-out pins Connect all the SJB connectors and make sure they seat The system is operating correctly at this correctly. time. The concern may have been caused Operate the system and verify the concern is still present. by a loose or corroded connector. TEST Is the concern still present? the system for normal operation. Pinpoint Test B: The Horn Is Always On Refer to Wiring Diagrams Cell 44, Horn/Cigar Lighter for schematic and connector information. rmal Operation The Smart Junction Box (SJB) supplies the switched and control voltage to the horn relay (integrated into the SJB). When the horn switch is pressed (part of the driver air bag module), ground is supplied to the horn relay, energizing the horn relay. The horn relay then provides voltage to the horn, enabling the horn to sound. This pinpoint test is intended to diagnose the following: Wiring, terminals or connectors Steering wheel harness Clockspring Horn switch (part of the driver air bag module) SJB B1 B2 B3 PINPOINT TEST B: THE HORN IS ALWAYS ON NOTICE: Use the correct probe adapter(s) when making measurements. Failure to use the correct probe adapter(s) may damage the connector. CHECK THE SJB HORN OUTPUT CIRCUIT FOR A SHORT TO VOLTAGE Ignition OFF. Disconnect: SJB C2280e. REPAIR circuit CRH02 (BU/WH) for a Does the horn continue to sound? short to voltage. TEST the system for normal operation. GO to B2. CHECK THE HORN SWITCH INPUT Disconnect: SJB C2280b. Connect: SJB C2280e. GO to B6. Does the horn continue to sound? GO to B3. CHECK THE HORN RELAY COIL GROUND CIRCUIT FOR A SHORT TO GROUND Depower the Supplemental Restraint System (SRS). Refer to Section B. Disconnect: Clockspring C218a.

7 Horn B3 PINPOINT TEST B: THE HORN IS ALWAYS ON CHECK THE HORN RELAY COIL GROUND CIRCUIT FOR A SHORT TO GROUND Measure the resistance between the clockspring C218a-8, circuit SRH01 (YE/RD), harness side and ground. B4 GO to B4. REPAIR circuit SRH01 (YE/RD) for a short to ground. REPOWER the SRS. REFER to Section B. TEST the system for Is the resistance greater than 10,000 ohms? normal operation. CHECK THE CLOCKSPRING FOR A SHORT TO GROUND Remove the driver air bag module. Refer to Section B. Connect: Clockspring C218a. Disconnect: Upper Clockspring C218b. Measure the resistance between the SJB C2280b-41, circuit SRH01 (YE/RD), harness side and ground. B5 GO to B5. INSTALL a new clockspring. REFER to Section B. TEST the system for Is the resistance greater than 10,000 ohms? normal operation. CHECK THE STEERING WHEEL HARNESS FOR SHORTS Inspect the steering wheel harness for shorts. Is the steering wheel harness OK? REPAIR or INSTALL a new driver air bag module. REFER to Section B. TEST the system for normal operation. REPAIR or INSTALL a new steering wheel harness. INSTALL the driver air bag module. REFER to Section B. TEST the system for normal operation.

8 Horn B6 PINPOINT TEST B: THE HORN IS ALWAYS ON CHECK FOR CORRECT SJB OPERATION Disconnect all the SJB connectors. Check for: INSTALL a new SJB. REFER to Section corrosion TEST the system for normal damaged pins operation. pushed-out pins Connect all the SJB connectors and make sure they seat The system is operating correctly at this correctly. time. The concern may have been caused Operate the system and verify the concern is still present. by a loose or corroded connector. TEST Is the concern still present? the system for normal operation.

SECTION Instrument Cluster and Panel Illumination

SECTION Instrument Cluster and Panel Illumination 413-00-i Instrument Cluster and Panel Illumination 413-00-i SECTION 413-00 Instrument Cluster and Panel Illumination CONTENTS PAGE DIAGNOSIS AND TESTING Instrument Cluster and Panel Illumination... 413-00-2