Pinpoint Test D: The Steering Wheel Control 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.

NOTE: Failure to disconnect the battery when instructed will result in false resistance readings. Refer to BATTERY, BATTERY MOUNTING & BATTERY CABLES article.

D1 CHECK THE OTHER DIMMABLE LIGHTING SWITCHES
- Ignition OFF.
- 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.
- Are all the dimmable switches inoperative?
- Yes : GO to PINPOINT TEST B .
- No : GO 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 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 VLN37 (BU/WH), harness side and ground.
  
  Fig 1: Measuring Voltage Between Clockspring C218a-16, Circuit VLN37 (BU/WH) And Ground
  Courtesy of FORD MOTOR CO.
- Is the voltage greater than 10 volts?
- Yes : GO to D3.
- No : REPAIR circuit VLN37 (BU/WH) for an open. REPOWER the SRS. REFER to SUPPLEMENTAL RESTRAINT SYSTEM article. TEST the system for normal operation.
D3 CHECK THE CLOCKSPRING GROUND FOR AN OPEN
- Disconnect: Negative Battery Cable.
- Measure the resistance between the clockspring C218a-5, circuit GD116 (BK/VT), harness side and ground.
  
  Fig 2: Measuring Resistance Between Clockspring C218a-5, Circuit GD116 (BK/VT) And Ground
  Courtesy of FORD MOTOR CO.
- Is the resistance less than 5 ohms?
- Yes : GO 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 C218a pin 5, component side and the upper clockspring connector pin 4, component side.
  
  Fig 3: Measuring Resistance Between Clockspring C218a Pin 5 And Upper Clockspring Connector Pin 4
  Courtesy of FORD MOTOR CO.
- Measure the resistance between the clockspring C218a pin 16, component side and the upper clockspring connector pin 7, component side.
  
  Fig 4: Measuring Resistance Between Clockspring C218a Pin 16 And Upper Clockspring Connector Pin 7
  Courtesy of FORD MOTOR CO.
- Are the resistances less than 5 ohms?
- Yes : GO to D5.
- No : INSTALL a new clockspring. INSTALL the driver air bag module. 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 switch(es). REFER to CRUISE CONTROL SYSTEM article or INFORMATION SYSTEM AND ENTERTAINMENT SYSTEM article 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.