Pinpoint Test E: The Steering Wheel Switch Illumination Is Inoperative

WARNING: This page is about a different car, the 2010 Mercury Mariner and 2010 Ford Escape. However, it is still accessible from the selected car via links, so may be relevant.

NOTE: Use the correct probe adapter(s) when making measurements. Failure to use the correct probe adapter(s) may damage the connector.

E1 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 C .
- No: GO to E2 .
E2 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 (SRS) DEPOWERING AND REPOWERING .
- Disconnect: Clockspring C218a.
- Connect: Negative Battery 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 C218-2, circuit VLN04 (VT/GY) harness side and ground.
  
  Fig 1: Checking Circuit VLN04 For Open
  Courtesy of FORD MOTOR CO.
- Is the voltage greater than 10 volts?
- Yes: GO to E3 .
- No: REPAIR circuit VLN04 (VT/GY) for an open. REPOWER the SRS . REFER to SUPPLEMENTAL RESTRAINT SYSTEM (SRS) DEPOWERING AND REPOWERING . TEST the system for normal operation.
E3 CHECK FOR VOLTAGE TO THE CLOCKSPRING USING THE CONNECTOR GROUND
- Measure the voltage between the clockspring C218-2, circuit VLN04 (VT/GY), harness side and the clockspring C218-7, circuit GD112 (BK/GN), harness side.
  
  Fig 2: Checking Circuit GD112 For Open
  Courtesy of FORD MOTOR CO.
- Is the voltage greater than 10 volts?
- Yes: GO to E4 .
- No: REPAIR circuit GD112 (BK/GN) for an open. REPOWER the SRS . REFER to SUPPLEMENTAL RESTRAINT SYSTEM (SRS) DEPOWERING AND REPOWERING . TEST the system for normal operation.
E4 CHECK THE CLOCKSPRING FOR AN OPEN
- Remove the driver air bag module. Refer to DRIVER AIR BAG MODULE .
- Disconnect: Upper Clockspring Connector.
- Measure the resistance between the clockspring C218 pin 2, component side and the upper clockspring connector pin 7, component side.
  
  Fig 3: Measuring Resistance Between Clockspring C218 Pin 2 And Upper Clockspring Connector Pin 7
  Courtesy of FORD MOTOR CO.
- Measure the resistance between the clockspring C218 pin 7, component side and the upper clockspring connector pin 4, component side.
  
  Fig 4: Measuring Resistance Between Clockspring C218 Pin 7 And Upper Clockspring Connector Pin 4
  Courtesy of FORD MOTOR CO.
- Are the resistances less than 5 ohms?
- Yes: GO to E5 .
- No: INSTALL a new clockspring. INSTALL the driver air bag module. REFER to DRIVER AIR BAG MODULE . TEST the system for normal operation.
E5 CHECK THE STEERING WHEEL HARNESS
- Inspect the steering wheel harness for opens or any damage.
- Is the steering wheel harness OK?
- Yes: INSTALL new steering wheel switch(es). REFER to CRUISE CONTROL SWITCH or STEERING WHEEL CONTROLS as necessary. INSTALL the driver air bag module. REFER to DRIVER AIR BAG MODULE . TEST the system for normal operation.
- No: REPAIR or INSTALL a new steering wheel harness. INSTALL the driver air bag module. REFER to DRIVER AIR BAG MODULE . TEST the system for normal operation.