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Pinpoint Test A: The Courtesy Lamps Are 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, Interior Lamps for schematic and connector information.

Normal Operation 

Fuse 18 (15A) in the central junction box (CJB) provides power through circuit 54 (LG/YE) to the lighting control module (LCM). The driver door module (DDM) monitors the LH front door ajar switch on circuit 867 (DB), and the remaining door ajar switches on circuit 627 (BK/OG). The door ajar switches provide a path for ground supplied through the ajar switches by circuit 57 (BK), indicating an open door. The DDM then sends a message over the standard corporate protocol (SCP) to command the LCM to supply power to the courtesy lamps on circuit 53 (BK/LB). The courtesy lamps are grounded through circuit 57 (BK).

This pinpoint test is intended to diagnose the following:

PINPOINT TEST A: THE COURTESY LAMPS ARE INOPERATIVE 

NOTE: The LCM may be configured for a police vehicle. In the police configuration, the LCM ignores the door ajar switch inputs for interior lighting. Check the LCM for correct configuration.
  1. A1 CHECK THE DRIVER DOOR AJAR INPUT 
    • Key in ON position.
    • Enter the following diagnostic mode on the diagnostic tool: DDM DataLogger
    • Monitor the DDM driver door PID (D_DR_SW) while opening and closing the driver door.
    • Does the DDM PID value agree with the door positions? 
    1. YES  : Go to  A2.
    2. NO  : Go to Pinpoint Test D .
  2. A2 CHECK THE PASSENGER DOOR AJAR INPUTS 
    • Monitor the DDM passenger door PID (P_DR_SW) while opening and closing the LH rear, RH front, and RH rear doors.
    • Do the DDM PID values agree with the door positions? 
    1. YES  : Go to  A3.
    2. NO  : Go to Pinpoint Test D .
  3. A3 CHECK CIRCUIT 54 (LG/YE) FOR AN OPEN 
    • Key in OFF position.
    • Disconnect: LCM C2145c
      • Fig 1: Checking Circuit For Open
      GF0014616Courtesy of FORD MOTOR CO.
    • Measure the voltage between the LCM C2145c-4, circuit 54 (LG/YE), harness side and ground.
    • Is the voltage greater than 10 volts? 
    1. YES  : Go to  A4.
    2. NO  : VERIFY the CJB fuse 18 (15A) is OK. If OK, REPAIR the circuit. TEST the system for normal operation.
  4. A4 CHECK CIRCUIT 53 (BK/LB) FOR AN OPEN 
      Fig 2: Connecting Fused Jumper Wire
      GF0014617Courtesy of FORD MOTOR CO.
      NOTE: If the fuse fails, repair circuit 53 (BK/LB) for a short to ground.
    • Connect a fused (5A) jumper wire between the LCM C2145c-4, circuit 54 (LG/YE), harness side and the LCM C2145c-5, circuit 53 (BK/LB), harness side.
    • Do the interior lamps illuminate? 
    1. YES  : REMOVE the jumper wire. Go to  A5.
    2. NO  : REMOVE the jumper wire. REPAIR the circuit. TEST the system for normal operation.
  5. A5 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. TEST the system for normal operation.
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