Pinpoint Test B: All DIMMABLE 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.

B1 CHECK THE INSTRUMENT PANEL DIMMER SWITCH
- Ignition OFF.
- Disconnect: Instrument Panel Dimmer Switch C2298 .
- Carry out the component test for the instrument panel dimmer switch.
  Refer to OEM WIRING DIAGRAMS COMPONENT TESTING .
Is the instrument panel dimmer switch OK?
- Yes : GO to B2 .
- No : INSTALL a new instrument panel dimmer switch. REFER to INSTRUMENT PANEL DIMMER SWITCH . CLEAR the DTCs. REPEAT the self-test.
B2 CHECK THE INSTRUMENT PANEL DIMMER SWITCH INPUT CIRCUIT FOR A SHORT TO VOLTAGE
- Disconnect: SJB C2280B .
- Ignition ON.
- Measure the voltage between the instrument panel dimmer switch C2298-1 , circuit VLN18 (BU/WH), harness side and ground.
  
  Fig 1: Measuring Voltage Between Instrument Panel Dimmer Switch C2298-1 And Ground
  Courtesy of FORD MOTOR CO.
Is any voltage present?
- Yes : REPAIR circuit VLN18 (BU/WH) for a short to voltage. CLEAR the DTCs. REPEAT the self-test.
- No : GO to B3 .
B3 CHECK THE INSTRUMENT PANEL DIMMER SWITCH RETURN CIRCUIT FOR A SHORT TO VOLTAGE
- Measure the voltage between the instrument panel dimmer switch C2298-4 , circuit RLN29 (WH/OG), harness side and ground.
  
  Fig 2: Measuring Voltage Between Instrument Panel Dimmer Switch C2298-4 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 B4 .
B4 CHECK THE INSTRUMENT PANEL DIMMER SWITCH INPUT CIRCUIT FOR A SHORT TO GROUND
- Ignition OFF.
- Measure the resistance between the instrument panel dimmer switch C2298-1 , circuit VLN18 (BU/WH), harness side and ground.
  
  Fig 3: Measuring Resistance Between Instrument Panel Dimmer Switch C2298-1 And Ground
  Courtesy of FORD MOTOR CO.
Is the resistance greater than 10, 000 ohms?
- Yes : GO to B5 .
- No : REPAIR circuit VLN18 (BU/WH) for a short to ground. TEST the system for normal operation.
B5 CHECK THE INSTRUMENT PANEL DIMMER SWITCH INPUT CIRCUIT FOR AN OPEN
- Measure the resistance between the instrument panel dimmer switch C2298-1 , circuit VLN18 (BU/WH), harness side and the SJB C2280B-34 , circuit VLN18 (BU/WH), harness side.
  
  Fig 4: Measuring Resistance Between Instrument Panel Dimmer Switch C2298-1, SJB C2280B-34 And Circuit VLN18 (BU/WH)
  Courtesy of FORD MOTOR CO.
Is the resistance less than 5 ohms?
- Yes : GO to B6 .
- No : REPAIR circuit VLN18 (BU/WH) for an open. CLEAR the DTCs. REPEAT the self-test.
B6 CHECK THE INSTRUMENT PANEL DIMMER SWITCH RETURN CIRCUIT FOR AN OPEN
- Measure the resistance between the instrument panel dimmer switch C2298-4 , circuit RLN29 (WH/OG), harness side and the SJB C2280B-33 , circuit RLN29 (WH/OG), harness side.
  
  Fig 5: Measuring Resistance Between Instrument Panel Dimmer Switch C2298-4 And SJB C2280B-33
  Courtesy of FORD MOTOR CO.
Is the resistance less than 5 ohms?
- Yes : GO to B7 .
- No : REPAIR circuit RLN29 (WH/OG) for an open. CLEAR the DTCs. REPEAT the self-test.
B7 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.