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Home >> Mercury >> 2009 >> Mariner Base, 2.5 7, AWD >> Repair and Diagnosis >> External Pages >> Different car >> Section 161 (Instrument Cluster Illumination & Instrument Panel Illumination) >> Diagnostic Tests >> Instrument Cluster & Panel Illumination >> Pinpoint Tests >> Pinpoint Test A: The Control Illumination Is Inoperative

Pinpoint Test A: The Control Illumination Is Inoperative

WARNING: This page is about a different car, the 2009 Mercury Grand Marquis and 2009 Ford Crown Victoria. However, it is still accessible from the selected car via links, so may be relevant.

Refer to appropriate SYSTEM WIRING DIAGRAMS article, Cluster and Panel Illumination for schematic and connector information.

Normal Operation 

The lighting control module (LCM) receives voltage from the central junction box (CJB) on circuit 54 (LG/YE). With the parking lamps on, the LCM generates a variable pulse width modulated (PWM) voltage which is distributed to the dimmable components on circuit 484 (OG/BK). The driver door module (DDM) generates a variable voltage which it distributed to the heating ventilation air conditioning (HVAC) module and the overhead console with moonroof on circuit 19 (LB/RD). Light intensity is adjusted by rotating the instrument panel dimmer switch.

This pinpoint test is intended to diagnose the following:

PINPOINT TEST A: THE CONTROL ILLUMINATION IS INOPERATIVE 

NOTE: Use the correct probe adapter(s) when making measurements. Failure to use the correct probe adapter(s) may damage the connector.
  1. A1 CHECK CIRCUIT 905 (GY/LB) FOR AN OPEN 
    • Key in OFF position.
    • Disconnect: LCM C2145c
    • Key in ON position.
      • Fig 1: Checking Circuit For Open
      GF0014427Courtesy of FORD MOTOR CO.
    • Measure the voltage between the LCM C2145c-17, circuit 905 (GY/LB), harness side and ground.
    • Is the voltage greater than 10 volts? 
    1. YES  : Go to  A2.
    2. NO  : VERIFY the CJB fuse 4 (10A) is OK. If OK, REPAIR the circuit. TEST the system for normal operation.
  2. A2 CHECK CIRCUIT 484 (OG/BK) FOR AN OPEN OR SHORT TO GROUND 
      Fig 2: Checking Circuit For Open Or Short To Ground
      GF0014428Courtesy of FORD MOTOR CO.
      NOTE: If the fuse fails, repair the short to ground in circuit 484 (OG/BK).
    • Connect a fused (10A) jumper wire between the LCM C2145c-17, circuit 905 (GY/LB), harness side and the LCM C2145c-3, circuit 484 (OG/BK), harness side.
    • Do the instrument panel lamps illuminate? 
    1. YES  : Go to  A3.
    2. NO  : REPAIR the circuit. TEST the system for normal operation.
  3. A3 CHECK CIRCUIT 676 (PK/OG) FOR AN OPEN 
    • Key in OFF position.
      • Fig 3: Checking Circuit For Open
      GF0014429Courtesy of FORD MOTOR CO.
    • Measure the resistance between the LCM C2145a-11, circuit 676 (PK/OG), harness side and ground; and between the LCM C2145c-7, circuit 676 (PK/OG), harness side and ground.
    • Are the resistances less than 5 ohms? 
    1. YES  : Go to  A4.
    2. NO  : REPAIR the circuit in question. TEST the system for normal operation.
  4. A4 CHECK FOR CORRECT LCM OPERATION 
    • Disconnect all the LCM connectors.
    • Check for:
      • corrosion
      • damaged pins
      • pushed-out pins
    • Connect all the LCM connectors and make sure they seat correctly.
    • Operate the system and verify the concern is still present.
    • Is the concern still present? 
    1. YES  : INSTALL a new LCM. REFER to MULTIFUNCTION ELECTRONIC MODULES article. TEST the system for normal operation.
    2. 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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