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Pinpoint Test C: The Courtesy Lamps Stay On Continuously

WARNING: This page is about a different car, the 2010 Lincoln Town Car. However, it is still accessible from the selected car via links, so may be relevant.

Refer to appropriate SYSTEM WIRING DIAGRAMS article, Driver Door Module for schematic and connector information.

Refer to appropriate SYSTEM WIRING DIAGRAMS article, Interior Lamps for schematic and connector information.

Normal Operation 

The driver door module (DDM) monitors the door ajar switch status for each door. When a door is open, the DDM signals the lighting control module (LCM) to supply power to the courtesy lamps. The courtesy lamps are powered through circuit 53 (BK/LB). The LCM also monitors the dome lamp switch status from the instrument panel dimmer switch through circuit 1034 (BK/WH). When the LCM recognizes that the dome lamps have been requested, the LCM supplies power to the courtesy lamps on circuit 53 (BK/LB).

This pinpoint test is intended to diagnose the following: 

PINPOINT TEST C: THE COURTESY LAMPS STAY ON CONTINUOUSLY 

NOTE: Use the correct probe adapter(s) when making measurements. Failure to use the correct probe adapter(s) may damage the connector.
  1. C1 CHECK THE DOOR AJAR PID STATUS WITH THE SCAN TOOL 
    • Key in ON position.
    • Close all the doors.
    • Enter the following diagnostic mode on the diagnostic tool: DDM DataLogger
    • Monitor the DDM door ajar switch PIDs (D_DR_SW and P_DR_SW).
    • Do the door ajar PIDs match the door positions? 
    1. YES  : Go to  C2.
    2. NO  : For the LH front door, go to  C3.

      For all other doors, go to  C5.

  2. C2 CHECK THE INSTRUMENT PANEL DIMMER SWITCH INPUT 
    • Enter the following diagnostic mode on the diagnostic tool: LCM DataLogger
    • Monitor the LCM dome lamp switch PID (DOMELM_SW) while using the instrument panel dimmer switch to turn the courtesy lamps on and off.
    • Does the LCM PID value agree with the switch positions? 
    1. YES  : Go to  C11.
    2. NO  : Go to  C9.
  3. C3 CHECK THE LH FRONT DOOR AJAR SWITCH FOR A SHORT TO GROUND 
    • Disconnect: LH Front Door Ajar Switch C526a
    • Enter the following diagnostic mode on the diagnostic tool: DDM DataLogger
    • Monitor the DDM driver door ajar switch PID (D_DR_SW).
    • Did the door ajar PID change with the switch disconnected? 
    1. YES  : INSTALL a new door ajar switch. REFER to HANDLES, LOCKS, LATCHES & ENTRY SYSTEMS article. CLEAR the DTCs. REPEAT the self-test.
    2. NO  : Go to  C4.
  4. C4 CHECK CIRCUIT 867 (DB) FOR A SHORT TO GROUND 
    • Key in OFF position.
    • Disconnect: DDM C501a
      • Fig 1: Checking Circuit For Short To Ground
      GF0014618Courtesy of FORD MOTOR CO.
    • Measure the resistance between the DDM C501a-22, circuit 867 (DB), harness side and ground.
    • Is the resistance greater than 10,000 ohms? 
    1. YES  : Go to  C13.
    2. NO  : REPAIR the circuit. CLEAR the DTCs. REPEAT the self-test.
  5. C5 CHECK THE RH FRONT DOOR AJAR SWITCH FOR A SHORT TO GROUND 
    • Disconnect: RH Front Door Ajar Switch C602a
    • Enter the following diagnostic mode on the diagnostic tool: DDM DataLogger
    • Monitor the DDM passenger door ajar switch PID (P_DR_SW).
    • Did the door ajar PID change with the switch disconnected? 
    1. YES  : INSTALL a new door ajar switch. REFER to HANDLES, LOCKS, LATCHES & ENTRY SYSTEMS article. CLEAR the DTCs. REPEAT the self-test.
    2. NO  : Go to  C6.
  6. C6 CHECK THE RH REAR DOOR AJAR SWITCH FOR A SHORT TO GROUND 
    • Disconnect: RH Rear Door Ajar Switch C820a
    • Enter the following diagnostic mode on the diagnostic tool: DDM DataLogger
    • Monitor the DDM passenger door ajar switch PID (P_DR_SW).
    • Did the door ajar PID change with the switch disconnected? 
    1. YES  : INSTALL a new door ajar switch. REFER to HANDLES, LOCKS, LATCHES & ENTRY SYSTEMS article. CLEAR the DTCs. REPEAT the self-test.
    2. NO  : Go to  C7.
  7. C7 CHECK THE LH REAR DOOR AJAR SWITCH FOR A SHORT TO GROUND 
    • Disconnect: LH Rear Door Ajar Switch C715a
    • Enter the following diagnostic mode on the diagnostic tool: DDM DataLogger
    • Monitor the DDM passenger door ajar switch PID (P_DR_SW).
    • Did the door ajar PID change with the switch disconnected? 
    1. YES  : INSTALL a new door ajar switch. REFER to HANDLES, LOCKS, LATCHES & ENTRY SYSTEMS article. CLEAR the DTCs. REPEAT the self-test.
    2. NO  : Go to  C8.
  8. C8 CHECK CIRCUIT 627 (BK/OG) FOR A SHORT TO GROUND 
    • Key in OFF position.
    • Disconnect: DDM C501b
      • Fig 2: Checking Circuit For Short To Ground
      GF0014619Courtesy of FORD MOTOR CO.
    • Measure the resistance between the DDM C501b-7, circuit 627 (BK/OG), harness side and ground.
    • Is the resistance greater than 10,000 ohms? 
    1. YES  : Go to  C13.
    2. NO  : REPAIR the circuit. CLEAR the DTCs. REPEAT the self-test.
  9. C9 CHECK THE INSTRUMENT PANEL DIMMER SWITCH 
    • Key in OFF position.
    • Disconnect: Instrument Panel Dimmer Switch C205b
      • NOTE: Make sure the doors are closed.
    • Observe the courtesy lamps.
    • Are the courtesy lamps still illuminated? 
    1. YES  : Go to  C10.
    2. NO  : INSTALL a new instrument panel dimmer switch. REFER to INSTRUMENT CLUSTER & PANEL ILLUMINATION article. CLEAR the DTCs. REPEAT the self-test.
  10. C10 CHECK CIRCUIT 1034 (BK/WH) FOR A SHORT TO GROUND 
    • Disconnect: LCM C2145b
      • Fig 3: Checking Circuit For Short To Ground
      GF0014620Courtesy of FORD MOTOR CO.
    • Measure the resistance between the headlamp switch C205b-5, circuit 1034 (BK/WH), harness side and ground.
    • Is the resistance greater than 10,000 ohms? 
    1. YES  : Go to  C12.
    2. NO  : REPAIR the circuit. CLEAR the DTCs. REPEAT the self-test.
  11. C11 CHECK CIRCUIT 53 (BK/LB) FOR A SHORT TO VOLTAGE 
    • Key in OFF position.
    • Disconnect: LCM C2145c
    • Observe the courtesy lamps.
    • Are the courtesy lamps still illuminated? 
    1. YES  : REPAIR the circuit. TEST the system for normal operation.
    2. NO  : Go to  C12.
  12. C12 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. CLEAR the DTCs. REPEAT the self-test.
  13. C13 CHECK FOR CORRECT DDM OPERATION 
    • Disconnect all the DDM connectors.
    • Check for:
      • corrosion
      • damaged pins
      • pushed-out pins
    • Connect all the DDM 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 DDM. 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. CLEAR the DTCs. REPEAT the self-test.
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