Pinpoint Test E: A Single Illumination Source Is Inoperative - Steering Wheel Control Switches

E1 CHECK VOLTAGE AT THE CLOCKSPRING LOWER CONNECTOR
- Remove the driver air bag module. Refer to SUPPLEMENTAL RESTRAINT SYSTEM .
- Disconnect: Clockspring Lower Connector C218b.
- Connect the restraint system diagnostic tool 418-F403 (2 req'd) to the driver air bag electrical connectors.
- Connect the battery. Refer to BATTERY, MOUNTING AND CABLES .
- Place the headlamp switch in the parking lamps ON position.
- Increase the instrument panel dim control switch to maximum brightness level.
- Measure the voltage between the clockspring lower C218b pin 3, circuit 1045 (DB/WH), harness side and ground.
  
  Fig 1: Measuring Voltage Between Clockspring Lower C218b Pin 3 And Ground
  Courtesy of FORD MOTOR CO.
- Is the voltage greater than 10 volts?
- Yes : GO to E2.
- No : REPAIR the circuit. TEST the system for normal operation. DISCONNECT the battery. REFER to BATTERY, MOUNTING AND CABLES . INSTALL the air bag. REFER to SUPPLEMENTAL RESTRAINT SYSTEM .
E2 CHECK GROUND AT THE CLOCKSPRING LOWER CONNECTOR
- Place the headlamp switch in the parking lamps OFF position.
- Measure the resistance between the steering wheel control switch C218b pin 7, circuit 57 (BK), harness side and ground.
  
  Fig 2: Measuring Resistance Between Steering Wheel Control Switch C218b Pin 7 And Ground
  Courtesy of FORD MOTOR CO.
- Is the resistance less than 5 ohms?
- Yes : GO to E3.
- No : REPAIR the circuit. TEST the system for normal operation. DISCONNECT the battery. REFER to BATTERY, MOUNTING AND CABLES . INSTALL the air bag. REFER to SUPPLEMENTAL RESTRAINT SYSTEM .
E3 CHECK VOLTAGE AT THE UPPER CLOCKSPRING CONNECTOR
- Connect: Clockspring Lower Connector C218b.
- Disconnect: Clockspring Upper Harness Connector.
- Place the headlamp switch in the parking lamps ON position.
- Increase the instrument panel dim control switch to maximum brightness level.
- Measure the voltage between the upper clockspring connector pin 3, circuit 1045 (DB/WH), component side and ground.
  
  Fig 3: Measuring Voltage Between Upper Clockspring Connector Pin 3 And Ground
  Courtesy of FORD MOTOR CO.
- Is the voltage greater than 10 volts?
- Yes : GO to E4.
- No : INSTALL a new clockspring. REFER to SUPPLEMENTAL RESTRAINT SYSTEM . TEST the system for normal operation. DISCONNECT the battery. REFER to BATTERY, MOUNTING AND CABLES . INSTALL the air bag. REFER to SUPPLEMENTAL RESTRAINT SYSTEM .
E4 CHECK GROUND AT THE UPPER CLOCKSPRING CONNECTOR
- Place the headlamp switch in the parking lamps OFF position.
- Measure the resistance between the upper clockspring connector pin 2, circuit 57 (BK), component side and ground.
  
  Fig 4: Measuring Resistance Between Upper Clockspring Connector Pin 2 And Ground
  Courtesy of FORD MOTOR CO.
- Is the resistance less than 5 ohms?
- Yes : INSTALL a new steering wheel control switch(es) and harness assembly kit. TEST the system for normal operation. DISCONNECT the battery. REFER to BATTERY, MOUNTING AND CABLES . INSTALL the air bag. REFER to SUPPLEMENTAL RESTRAINT SYSTEM .
- No : INSTALL a new clockspring. REFER to SUPPLEMENTAL RESTRAINT SYSTEM . TEST the system for normal operation. DISCONNECT the battery. REFER to BATTERY, MOUNTING AND CABLES . INSTALL the air bag. REFER to SUPPLEMENTAL RESTRAINT SYSTEM .