Pinpoint Test D: All Instrument Panel Illumination Does Not Dim

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

D1 CHECK THE INSTRUMENT PANEL DIMMER SWITCH
- Ignition OFF.
- Disconnect: Instrument Panel Dimmer Switch C2065.
- Carry out the component test for the instrument panel dimmer switch.
  Refer to SYSTEM WIRING DIAGRAMS - EXPEDITION , SYSTEM WIRING DIAGRAMS - EXPEDITION EL , SYSTEM WIRING DIAGRAMS - NAVIGATOR or SYSTEM WIRING DIAGRAMS - NAVIGATOR L article for component testing.
- Is the instrument panel dimmer switch OK?
- Yes: GO to D2 .
- No: INSTALL a new instrument panel dimmer switch. REFER to INSTRUMENT PANEL DIMMER SWITCH . CLEAR the DTCs. REPEAT the self-test.
D2 CHECK THE INSTRUMENT PANEL DIMMER SWITCH INPUT CIRCUIT FOR A SHORT TO VOLTAGE
- Disconnect: SJB C2280d.
- Ignition ON.
- Measure the voltage between the instrument panel dimmer switch C2065-6, circuit CLN27 (WH/BN), harness side and ground.
  
  Fig 1: Measuring Voltage Between Instrument Panel Dimmer Switch C2065-6, Circuit CLN27 (WH/BN), Harness Side And Ground
  Courtesy of FORD MOTOR CO.
- Is any voltage present?
- Yes: REPAIR circuit CLN27 (WH/BN) for a short to voltage. CLEAR the DTCs. REPEAT the self-test.
- No: GO to D3 .
D3 CHECK THE INSTRUMENT PANEL DIMMER SWITCH RETURN CIRCUIT FOR A SHORT TO VOLTAGE
- Measure the voltage between the instrument panel dimmer switch C2065-4, circuit RLN29 (WH/OG), harness side and ground.
  
  Fig 2: Measuring Voltage Between Instrument Panel Dimmer Switch C2065-4, Circuit RLN29 (WH/OG), Harness Side And Ground
  Courtesy of FORD MOTOR CO.
- Is any voltage present?
- Yes: REPAIR circuit RLN29 (WH/OG) for a short to voltage. CLEAR the DTCs. REPEAT the self-test.
- No: GO to D4 .
D4 CHECK THE INSTRUMENT PANEL DIMMER SWITCH INPUT CIRCUIT FOR AN OPEN
- Ignition OFF.
- Measure the resistance between the instrument panel dimmer switch C2065-6, circuit CLN27 (WH/BN), harness side and the SJB C2280d-34, circuit CLN27 (WH/BN), harness side.
  
  Fig 3: Measuring Resistance Between Instrument Panel Dimmer Switch C2065-6, Circuit CLN27 (WH/BN) And Harness Side
  Courtesy of FORD MOTOR CO.
- Is the resistance less than 5 ohms?
- Yes: GO to D5 .
- No: REPAIR circuit CLN27 (WH/BN) for an open. CLEAR the DTCs. REPEAT the self-test.
D5 CHECK THE INSTRUMENT PANEL DIMMER SWITCH RETURN CIRCUIT FOR AN OPEN
- Measure the resistance between the instrument panel dimmer switch C2065-4, circuit RLN29 (WH/OG), harness side and the SJB C2280d-33, circuit RLN29 (WH/OG), harness side.
  
  Fig 4: Measuring Resistance Between Instrument Panel Dimmer Switch C2065-4, Circuit RLN29 (WH/OG) And Harness Side
  Courtesy of FORD MOTOR CO.
- Is the resistance less than 5 ohms?
- Yes: GO to D6 .
- No: REPAIR circuit RLN29 (WH/OG) for an open. CLEAR the DTCs. REPEAT the self-test.
D6 CHECK THE INSTRUMENT PANEL DIMMER SWITCH INPUT CIRCUIT FOR A SHORT TO GROUND
- Ignition OFF.
- Place the headlamp switch in the OFF position
- Disconnect: SJB C2280b.
- Measure the resistance between the instrument panel dimmer switch C2065-4, circuit CLN27 (WH/BN), harness side and ground.
  
  Fig 5: Measuring Resistance Between Instrument Panel Dimmer Switch C2065-4, Circuit CLN27 (WH/BN), Harness Side And Ground
  Courtesy of FORD MOTOR CO.
- Is the resistance greater than 10,000 ohms?
- Yes: GO to D7 .
- No: REPAIR circuit CLN27 (WH/BN) for a short to ground. TEST the system for normal operation.
D7 CHECK FOR CORRECT SJB OPERATION
- Disconnect all the SJB connectors.
- Check for:
  - corrosion
  - damaged pins
  - pushed-out pins
- Connect all the SJB 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 SJB . REFER to MULTIFUNCTION ELECTRONIC MODULES . 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. CLEAR the DTCs. REPEAT the self-test.