Pinpoint Test B: The Instrument Cluster Illumination Is Inoperative

B1 CHECK THE VOLTAGE TO THE INSTRUMENT CLUSTER ILLUMINATION
- Key in OFF position.
- Disconnect: Instrument Cluster C220c.
- Place the headlamp switch in the ON position.
- Rotate the panel dimmer switch to the full illumination position.
- Measure the voltage between the instrument cluster C220c pin 16, circuit 19 (LB/RD), harness side and ground.
- Is the voltage greater than 10 volts?
- Yes : GO to B2.
- No : REPAIR the circuit. TEST the system for normal operation.
B2 CHECK THE GROUND TO THE INSTRUMENT CLUSTER
- Place the headlamp switch in the OFF position.
- Measure the resistance between the instrument cluster C220c pin 15, circuit 57 (BK), harness side and ground.
  
  Fig 2: Measuring Resistance Between Instrument Cluster C220C Pin 15, Circuit 57 (BK), Harness Side And Ground
  Courtesy of FORD MOTOR CO.
- Is the resistance less than 5 ohms?
- Yes : GO to B3.
- No : REPAIR the circuit. TEST the system for normal operation.
B3 CHECK FOR CORRECT INSTRUMENT CLUSTER OPERATION
- Disconnect all the instrument cluster connectors.
- Check for:
  - corrosion
  - pushed-out pins
- Connect all the instrument cluster connectors and make sure they seat correctly.
- Operate the system and verify the concern is still present.
- Is the concern still present?
- Yes : INSTALL a new instrument cluster. REFER to INSTRUMENT CLUSTER . TEST the system for normal operation.
- No : The system is operating correctly at this time. The concern may have been caused by a loose or corroded connector.