Pinpoint Test D: The Steering Wheel Switch Illumination Is Inoperative

NOTE: 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
- Ignition OFF.
- Place the headlamp switch in the PARKING LAMPS ON position.
- Push the instrument panel dimmer switch to the full illumination position and observe the other dimmable switches.
- Are all the dimmable switches inoperative?
- Yes : Refer to PINPOINT TEST B .
- No : Refer to D2.
D2 CHECK FOR VOLTAGE TO THE CLOCKSPRING
- Place the headlamp switch in the OFF position.
- Depower the Supplemental Restraint System (SRS). Refer to SUPPLEMENTAL RESTRAINT SYSTEM Article.
- Disconnect: Clockspring C218a.
- Connect: Negative Battery Cable.
- Place the headlamp switch in the PARKING LAMPS ON position.
- Push the instrument panel dimmer switch to the full illumination position.
- Measure the voltage between the clockspring C218a-16, circuit VLN04 (VT/GY), harness side and ground.
  
  Fig 1: Measuring Voltage Between Clockspring C218A-16, Circuit VLN04 (VT/GY), Harness Side And Ground
  Courtesy of FORD MOTOR CO.
- Is the voltage greater than 10 volts?
- Yes : Refer to D3.
- No : REPAIR circuit VLN04 (VT/GY) for an open. REPOWER the SRS. REFER to SUPPLEMENTAL RESTRAINT SYSTEM Article. TEST the system for normal operation.
D3 CHECK FOR VOLTAGE TO THE CLOCKSPRING USING THE CONNECTOR GROUND
- Measure the voltage between the clockspring C218a-16, circuit VLN04 (VT/GY), harness side and the clockspring C218a-5, circuit GD116 (BK/VT), harness side.
  
  Fig 2: Measuring Voltage Between Clockspring C218A-16, Circuit VLN04 (VT/GY) And Clockspring C218A-5, Circuit GD116 (BK/VT)
  Courtesy of FORD MOTOR CO.
- Is the voltage greater than 10 volts?
- Yes : Refer to D4.
- No : REPAIR circuit GD116 (BK/VT) for an open. 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.
- Measure the resistance between the clockspring C2274 pin 5, component side and the upper clockspring connector pin 4, component side.
  
  Fig 3: Measuring Resistance Between Clockspring C2274 Pin 5 And Upper Clockspring Connector Pin 4, Component Side
  Courtesy of FORD MOTOR CO.
- Measure the resistance between the clockspring C2274 pin 16, component side and the upper clockspring connector pin 7, component side.
  
  Fig 4: Measuring Resistance Between Clockspring C2274 Pin 16 And Upper Clockspring Connector Pin 7, Component Side
  Courtesy of FORD MOTOR CO.
- Are the resistances less than 5 ohms?
- Yes : Refer to D5.
- No : INSTALL a new clockspring. REFER to SUPPLEMENTAL RESTRAINT SYSTEM Article.TEST the system for normal operation.
D5 CHECK THE STEERING WHEEL HARNESS
- Inspect the steering wheel harness for opens.
- Is the steering wheel harness OK?
- Yes : INSTALL a new steering wheel control switch. REFER to CRUISE CONTROL SYSTEM Article (cruise control switch) or INFORMATION SYSTEM AND ENTERTAINMENT SYSTEM Article (audio control switch) as necessary. INSTALL the driver air bag module. REFER to SUPPLEMENTAL RESTRAINT SYSTEM Article. TEST the system for normal operation.
- No : REPAIR or INSTALL a new steering wheel harness. INSTALL the driver air bag module. REFER to SUPPLEMENTAL RESTRAINT SYSTEM Article. TEST the system for normal operation.