Pinpoint Test B: The Instrument Cluster Illumination Is Inoperative

WARNING: This page is about a different car, the 2005 Ford RV Cutaway, 2005 Ford Econoline, 2005 Ford E450 Super Duty, and 2005 Ford Cutaway. However, it is still accessible from the selected car via links, so may be relevant.

B1 CHECK CIRCUIT 19 (LB/RD) FOR VOLTAGE
- Key in OFF position.
- Disconnect: Instrument Cluster C220b.
- Place the headlamp switch in the PARK position and rotate the headlamp switch knob fully counterclockwise without turning on the interior lamps.
- Measure the voltage between the instrument cluster C220b pin 26, circuit 19 (LB/RD), harness side and ground.
  
  Fig 1: Measuring Voltage Between Instrument Cluster And Ground
  Courtesy of FORD MOTOR CO.
- Is the voltage greater than 10 volts?
- Yes : GO to B2.
- No : REPAIR the circuit. TEST the system for normal operation.
B2 CHECK CIRCUIT 57 (BK) FOR AN OPEN
- Disconnect: Instrument Cluster C220a.
- Measure the resistance between the instrument cluster C220a pin 10, circuit 57 (BK), harness side and ground.
  
  Fig 2: Measuring Resistance Between Instrument Cluster And Ground
  Courtesy of FORD MOTOR CO.
- Is the resistance less than 5 ohms?
- Yes : INSTALL a new instrument cluster. REFER to INSTRUMENT CLUSTER . TEST the system for normal operation.
- No : REPAIR the circuit. TEST the system for normal operation.