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Home >> Mercury >> 2005 >> Montego Base, AWD >> Repair and Diagnosis >> Accessories & Equipment >> Gauges & Instrument Panels >> Instrument Cluster And Panel Illumination >> Diagnosis And Testing >> Instrument Cluster and Panel Illumination >> Pinpoint Test >> Pinpoint Test F: The Control Illumination Does Not Dim >> Testing

Pinpoint Test F: The Control Illumination Does Not Dim: Testing

  1. F1 CHECK THE EXTERIOR LAMP OPERATION 
    • Place the headlamp switch in the parking lamps on position.
    • Are the parking lamps illuminated? 
    • Yes  : GO to F2.
    • No  : REFER to EXTERIOR LIGHTING to continue diagnosis of the parking lamps.
  2. F2 CHECK THE INSTRUMENT PANEL DIMMER SWITCH CIRCUITRY FOR AN OPEN 
    • Key in OFF position.
    • Disconnect: Instrument Panel Dimmer Switch C2065.
    • Disconnect: Smart Junction Box (SJB) C2280d.
    • Measure the resistance between the SJB C2280d-29, circuit 1403 (BK/WH), harness side and the instrument panel dimmer switch, 2065-6, circuit 1403 (BK/WH), harness side; and between the SJB C2280d-22, circuit 1036 (BN/WH), harness side and the instrument panel dimmer switch C2065-4, circuit 1036 (BN/WH), harness side.
      Fig 1: Measuring Resistance Between SJB C2280D-29 And Instrument Panel Dimmer Switch
      G03992521Courtesy of FORD MOTOR CO.
    • Are the resistances less than 5 ohms? 
    • Yes  : GO to F3.
    • No  : REPAIR the circuit in question. TEST the system for normal operation.
  3. F3 CHECK THE INSTRUMENT PANEL DIMMER SWITCH CIRCUITRY FOR A SHORT TO GROUND 
    • Measure the resistance between the SJB C2280d-29, circuit 1403 (BK/WH), harness side and ground; and between the SJB C2280d-22, circuit 1036 (BN/WH), harness side and ground.
      Fig 2: Measuring Resistance Between SJB C2280D-29 And Ground
      G03992522Courtesy of FORD MOTOR CO.
    • Are the resistances greater than 10,000 ohms? 
    • Yes  : GO to F4.
    • No  : REPAIR the circuit in question. TEST the system for normal operation.
  4. F4 CHECK THE INSTRUMENT PANEL DIMMER SWITCH CIRCUITRY FOR A SHORT TO VOLTAGE 
    • Key in ON position.
    • Measure the voltage between the SJB C2280d-29, circuit 1403 (BK/WH), harness side and ground; and between the SJB C2280d-22, circuit 1036 (BN/WH), harness side and ground.
      Fig 3: Measuring Voltage Between SJB C2280D-29 And Ground
      G03992523Courtesy of FORD MOTOR CO.
    • Is any voltage present? 
    • Yes  : REPAIR the circuit in question. TEST the system for normal operation.
    • No  : GO to F5.
  5. F5 CHECK THE INSTRUMENT PANEL DIMMER SWITCH CIRCUITRY FOR A SHORT TO VOLTAGE 
    • While rotating the instrument panel dimmer switch wheel from the low to the full illumination position, measure the resistance between the SJB C2280d-29, circuit 1403 (BK/WH), harness side and the SJB C2280d-22, circuit 1036 (BN/WH), harness side.
      Fig 4: Measuring Resistance Between SJB C2280D-29 And SJB C2280D-22
      G03992524Courtesy of FORD MOTOR CO.
    • Does the resistance value change while rotating the instrument panel dimmer switch wheel? 
    • Yes  : GO to F6.
    • No  : INSTALL a new instrument panel dimmer switch. REFER to EXTERIOR LIGHTING . TEST the system for normal operation.
  6. F6 CHECK FOR CORRECT SJB OPERATION 
    • Disconnect all the SJB connectors.
    • Check for:
      • corrosion
      • 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.
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