Pinpoint Test D: The Steering Wheel Control Illumination Is Inoperative
Refer to appropriate SYSTEM WIRING DIAGRAM article for Cluster and Panel Illumination schematic and connector information.
Normal Operation
The smart junction box (SJB) sends a pulse width modulated (PWM) voltage to the steering wheel controls through circuit VLN04 (VT/GY) (Edge) or circuit VLN37 (BU/WH) (MKX) to the clockspring. The voltage passes through the clockspring to the steering wheel control switches. Ground to the clockspring is supplied through circuit GD116 (BK/VT).
This pinpoint test is intended to diagnose the following:
- Wiring, terminals or connectors
- Steering wheel control switch(es)
- Steering wheel control switch harness
- Clockspring
PINPOINT TEST D: THE STEERING WHEEL CONTROL ILLUMINATION IS INOPERATIVE
CAUTION:
Use the correct probe adapter(s) when making measurements. Failure to use the correct probe adapter(s) may damage the connector.
- D1 CHECK THE OTHER DIMMABLE LIGHTING SWITCHES
- Key in OFF position.
- Place the headlamp switch in the PARKING LAMPS ON position.
- Rotate the instrument panel dimmer switch to the full illumination position and observe other dimmable switches (door lock switches, hazard lamp switch, headlamp switch for example).
- Are all the dimmable switches inoperative?
- YES : Go to Pinpoint Test A .
- NO : Go to D2.
- D2 CHECK CIRCUIT VLN04 (VT/GY) (EDGE) OR CIRCUIT VLN37 (BU/WH) (MKX) FOR AN OPEN
- Place the headlamp switch in the OFF position.
- Depower the supplemental restraint system (SRS). Refer to SUPPLEMENTAL RESTRAINT SYSTEM article.
- Disconnect: Clockspring C218a
- Connect the battery ground cable.
- Place the headlamp switch in the PARKING LAMPS ON position.
- Rotate the instrument panel dimmer switch to the full illumination position.
- Measure the voltage between the clockspring C218a-16, circuit VLN04 (VT/GY) (Edge) or circuit VLN37 (BU/WH) (MKX), harness side and ground.
- Is the voltage greater than 10 volts?
Fig 1: Measuring Voltage Between Clockspring C218A-16, Circuit VLN04 (VT/GY) (Edge) Or Circuit VLN37 (BU/WH) (MKX)Courtesy of FORD MOTOR CO.
- YES : TURN the parking lamps off. Go to D3.
- NO : REPAIR the circuit. REPOWER the SRS. REFER to SUPPLEMENTAL RESTRAINT SYSTEM article. TEST the system for normal operation.
- D3 CHECK CIRCUIT GD116 (BK/VT) FOR AN OPEN
- Measure the resistance between the clockspring C218a-7, circuit GD116 (BK/VT), harness side and ground.
- Is the resistance less than 5 ohms?
Courtesy of FORD MOTOR CO.
- YES : Go to D4.
- NO : REPAIR the circuit. REPOWER the SRS. REFER to SUPPLEMENTAL RESTRAINT SYSTEM article. TEST the system for normal operation.
- D4 CHECK THE CLOCKSPRING FOR AN OPEN
- Remove the driver air bag module. Refer to SUPPLEMENTAL RESTRAINT SYSTEM article.
- Disconnect: Upper Clockspring Connector C218b
- Measure the resistance between the clockspring C218a pin 16, component side and the upper clockspring C218b pin 7, component side.
- Measure the resistance between the clockspring C218a pin 7, component side and the upper clockspring C218b pin 2, component side.
- Are the resistances less than 5 ohms?
Courtesy of FORD MOTOR CO.
Courtesy of FORD MOTOR CO.
- YES : Go to D5.
- NO : INSTALL a new clockspring. REFER to SUPPLEMENTAL RESTRAINT SYSTEM article. INSTALL the driver air bag module. REFER to SUPPLEMENTAL RESTRAINT SYSTEM article. TEST the system for normal operation.
- D5 CHECK THE STEERING WHEEL HARNESS CIRCUIT VLN04 (VT/GY) (EDGE) OR CIRCUIT VLN37 (BU/WH) (MKX) FOR AN OPEN
- Disconnect: LH Steering Wheel Switches C2998
- Disconnect: RH Steering Wheel Switches C2999
- Measure the resistance between the upper clockspring connector C218b-7, circuit VLN04 (VT/GY), harness side and the LH steering wheel switches C2998-2, circuit VLN04 (VT/GY), harness side; and between the upper clockspring connector C218b-7, circuit VLN04 (VT/GY), harness side and the RH steering wheel switches C2999-1, circuit VLN04 (VT/GY), harness side.
- Are the resistances less than 5 ohms?
Fig 5: Measuring Resistance Between Upper Clockspring Connector C218B-7, Circuit VLN04 (VT/GY) & LH Steering Wheel Switches C2998-2Courtesy of FORD MOTOR CO.
- YES : Go to D6.
- NO : REPAIR the circuit in question. INSTALL the driver air bag module. REFER to SUPPLEMENTAL RESTRAINT SYSTEM article. TEST the system for normal operation.
- D6 CHECK CIRCUIT GD165 (BK) FOR AN OPEN
- Measure the resistance between the clockspring C218b-2, circuit GD165 (BK), harness side, and the LH steering wheel switch C2998-4, circuit GD165 (BK), harness side; and between the clockspring C218b-2, circuit GD165 (BK), harness side, and the RH steering wheel switch C2999-3, circuit GD165 (BK), harness side.
- Is the resistance less than 5 ohms?
Fig 6: Measuring Resistance Between Clockspring C218B-2, Circuit GD165 (BK) & LH Steering Wheel Switch C2998-4Courtesy of FORD MOTOR CO.
- YES : INSTALL a new speed control switch or steering wheel controls as necessary. REFER to SPEED CONTROL article or INFORMATION AND ENTERTAINMENT SYSTEMS article. INSTALL the driver air bag module. REFER to SUPPLEMENTAL RESTRAINT SYSTEM article. TEST the system for normal operation.
- NO : REPAIR the circuit. INSTALL the driver air bag module. REFER to SUPPLEMENTAL RESTRAINT SYSTEM article. TEST the system for normal operation.