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 EXTERIOR LIGHTING OPERATION
- Place the headlamp switch in each of its positions while observing the exterior lamps.
- Do the exterior lamps operate correctly?
- Yes: GO to B2.
- No: Refer to EXTERIOR LIGHTING .
B2 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 COMPONENT TESTING for component testing.
- Is the instrument panel dimmer switch OK?
- Yes: GO to B3.
- No: INSTALL a new instrument panel dimmer switch. REFER to INSTRUMENT PANEL DIMMER SWITCH . TEST the system for normal operation.
B3 CHECK THE INSTRUMENT PANEL DIMMER SWITCH INPUT CIRCUIT FOR A SHORT TO VOLTAGE
- Disconnect: SJB C2280b.
- Start the engine.
- Measure the voltage between the instrument panel dimmer switch C2065-6, circuit VLN18 (BU/WH), harness side and ground.
  
  Fig 1: Checking Circuit VLN18 For Short To Voltage
  Courtesy of FORD MOTOR CO.
- Is any voltage present?
- Yes: REPAIR circuit VLN18 (BU/WH) for a short to voltage. TEST the system for normal operation.
- No: GO to B4.
B4 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: Checking Circuit RLN29 For Short To Voltage
  Courtesy of FORD MOTOR CO.
- Is any voltage present?
- Yes: REPAIR circuit RLN29 (WH/OG) for a short to voltage. TEST the system for normal operation.
- No: GO to B5.
B5 CHECK THE INSTRUMENT PANEL DIMMER SWITCH INPUT CIRCUIT FOR A SHORT TO GROUND
- Ignition OFF.
- Measure the resistance between the instrument panel dimmer switch C2065-6, circuit VLN18 (WH/BN), harness side and ground.
  
  Fig 3: Checking Circuit VLN18 For Short To Ground
  Courtesy of FORD MOTOR CO.
- Is the resistance greater than 10,000 ohms?
- Yes: GO to B6.
- No: REPAIR circuit VLN18 (BU/WH) for a short to ground. TEST the system for normal operation.
B6 CHECK THE INSTRUMENT PANEL DIMMER SWITCH INPUT CIRCUIT FOR AN OPEN
- Measure the resistance between the instrument panel dimmer switch C2065-6, circuit VLN18 (BU/WH), harness side and the SJB C2280b-34, circuit VLN18 (BU/WH), harness side.
  
  Fig 4: Checking Circuit VLN18 For An Open
  Courtesy of FORD MOTOR CO.
- Is the resistance less than 5 ohms?
- Yes: GO to B7.
- No: REPAIR circuit VLN18 (BU/WH) for an open. TEST the system for normal operation.
B7 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 C2280b-33, circuit RLN29 (WH/OG), harness side.
  
  Fig 5: Checking Circuit RLN29 For An Open
  Courtesy of FORD MOTOR CO.
- Is the resistance less than 5 ohms?
- Yes: GO to B8.
- No: REPAIR circuit RLN29 (WH/OG) for an open. TEST the system for normal operation.
B8 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.