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Home >> Ford >> 2000 >> Taurus LX, 3.0 2, AX4N >> Repair and Diagnosis >> External Pages >> Different car >> Section 1549 (Instrument Cluster Illumination And Panel Illumination) >> Diagnosis And Testing >> Instrument Cluster and Panel Illumination >> Pinpoint Tests >> Pinpoint Test B: All Dimmable Illumination Does Not Dim >> Pinpoint Test B: All DIMMABLE Illumination Does Not Dim

Pinpoint Test B: All DIMMABLE Illumination Does Not Dim

WARNING: This page is about a different car, the 2010 Mercury Mariner and 2010 Ford Escape. However, it is still accessible from the selected car via links, so may be relevant.
NOTE: Use the correct probe adapter(s) when making measurements. Failure to use the correct probe adapter(s) may damage the connector.
NOTE: Calibrate the instrument panel dimmer switch by rotating the dimmer switch from the full dim position to the dome on position before continuing diagnostics.
  1. 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? 
  2. 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 (Escape & Mariner), COMPONENT TESTING (Hybrid) 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.
  3. B3 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 C2065-6, circuit VLN18 (BU/WH), harness side and ground.
      Fig 1: Checking Circuit VLN18 For Short To Voltage
      G06064794Courtesy 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 B4  .
  4. 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 CLN04 (BU/BN), harness side and ground.
      Fig 2: Checking Circuit For Short To Voltage
      G06064793Courtesy of FORD MOTOR CO.
    • Is any voltage present? 
    • Yes:  REPAIR circuit CLN04 (BU/BN) for a short to voltage. CLEAR the DTCs. REPEAT the self-test.
    • No:  GO to B5  .
  5. 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 (BU/WH), harness side and ground.
      Fig 3: Checking Circuit VLN18 For Short To Ground
      G06390628Courtesy 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. CLEAR the DTCs. REPEAT the self-test.
  6. B6 CHECK THE INSTRUMENT PANEL DIMMER SWITCH RETURN CIRCUIT FOR A SHORT TO GROUND 
    • Measure the resistance between the instrument panel dimmer switch C2065-4, circuit CLN04 (BU/BN), harness side and ground.
      Fig 4: Checking Circuit For Short To Ground
      G06133386Courtesy of FORD MOTOR CO.
    • Is the resistance greater than 10,000 ohms? 
    • Yes:  GO to B7  .
    • No:  REPAIR circuit CLN04 (BU/BN) for a short to ground. CLEAR the DTCs. REPEAT the self-test.
  7. B7 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 5: Checking Circuit VLN18 For Open
      G06133393Courtesy of FORD MOTOR CO.
    • Is the resistance less than 5 ohms? 
    • Yes:  GO to B8  .
    • No:  REPAIR circuit VLN18 (BU/WH) for an open. CLEAR the DTCs. REPEAT the self-test.
  8. B8 CHECK THE INSTRUMENT PANEL DIMMER SWITCH RETURN CIRCUIT FOR AN OPEN 
    • Measure the resistance between the instrument panel dimmer switch C2065-4, circuit CLN04 (BU/BN), harness side and the SJB  C2280b-33, circuit CLN04 (BU/BN), harness side.
      Fig 6: Checking Circuit CLN04 For Open
      G06133394Courtesy of FORD MOTOR CO.
    • Is the resistance less than 5 ohms? 
    • Yes:  GO to B9  .
    • No:  REPAIR circuit CLN04 (BU/BN) for an open. CLEAR the DTCs. REPEAT the self-test.
  9. B9 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 SMART JUNCTION BOX (SJB) . 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.