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Pinpoint Test C: One Or Both Low Beams Are On Continuously

  1. Refer to HEADLAMPS/AUTOLAMPS for schematic and connector information.

    Normal Operation and Fault Conditions 

    REFER to: Exterior Lighting - Overview  . REFER to: Exterior Lighting - System Operation and Component Description  .

    DTC Fault Trigger Conditions 

    DTC Description Fault Trigger Condition
    BCM B1533:02 Headlamp Switch Module: General Signal Failure A continuous memory and on-demand DTC that sets when the BCM is missing data from the messages sent from the headlamp switch over the LIN circuit.
    BCM B1533:08 Headlamp Switch Module: Bus Signal/Message Failures A continuous memory and on-demand DTC that sets when the BCM has lost communication with the headlamp switch over the LIN circuit.
    BCM B1533:49 Headlamp Switch Module: Internal Electronic Failure A continuous memory and on-demand DTC that sets when the BCM message from the headlamp switch over the LIN circuit the headlamps switch has an internal failure.
    BCM B1533:56 Headlamp Switch Module: Invalid/Incompatible Configuration A continuous memory and on-demand DTC that sets when the BCM, over the LIN circuit, has detected that the headlamp switch is not properly configured.
    HCM B103C:01 Left Headlamp Control: General Electrical Failure A continuous memory and on-demand DTC that sets in the HCM if an internal headlamp failure of the adaptive front lighting components is detected.
    HCM B103D:01 Right Headlamp Control: General Electrical Failure A continuous memory and on-demand DTC that sets in the HCM if an internal headlamp failure of the adaptive front lighting components is detected.
    HCM B1087:00 LIN Bus "A": No Sub Type Information A continuous memory and on-demand DTC that sets in the HCM if communication is lost with the adaptive front lighting module.
    HCM B1088:00 LIN Bus "B": No Sub Type Information A continuous memory and on-demand DTC that sets in the HCM if communication is lost with the adaptive front lighting module.

    Possible Sources 

    • Wiring, terminals or connectors
    • Headlamp switch
    • Headlamp assembly
    • LED module
    • HCM
    • BCM

    Visual Inspection and Pre-checks 

    • Inspect the headlamp switch for damage.

  2. C1 CHECK LOW BEAMS OPERATION

    • Ignition ON.

    • Place the headlamp switch in the OFF position.

    • Observe the operation of the LH and RH low beam.

    Are both low beams illuminated? 

    Yes  GO to  C2
    No  GO to  C8

  3. C2 CHECK FOR BCM (BODY CONTROL MODULE) DIAGNOSTIC TROUBLE CODES (DTCS)

    • Ignition ON.

    • Using a diagnostic scan tool, perform the BCM self-test.

    Is DTC B1533:02, B1533:08, B1533:49 or B1533:56 present? 

    Yes  For BCMDTC B1533:02 or B1533:08, GO to  C3 For BCMDTC B1533:49, INSTALL a new headlamp switch. REFER to: Headlamp Switch . For BCMDTC B1533:56, using the diagnostic scan tool, execute the BCMLIN New Module Initialization routine. Follow the diagnostic scan tool directions. If the initialization routine fails, INSTALL a new headlamp switch. REFER to: Headlamp Switch .
    No  GO to  C15

  4. C3 CHECK THE HEADLAMP SWITCH VOLTAGE SUPPLY CIRCUIT FOR AN OPEN

    • Ignition OFF.

    • Disconnect: Headlamp Switch C205.

    • Ignition ON.

    • Measure:
      Positive Lead Measurement / Action Negative Lead
      C205-8
      GFD620822Courtesy of FORD MOTOR COMPANY
      		 Ground

    Is the voltage greater than 11 volts? 

    Yes  GO to  C4
    No  VERIFY the BCM fuse 19 (5A) is OK. If OK, REPAIR the circuit. If not OK, REFER to the OEM ELECTRICAL WIRING DIAGRAM INTRODUCTION to identify the possible causes of the circuit short.

  5. C4 CHECK THE HEADLAMP SWITCH GROUND CIRCUIT FOR AN OPEN

    • Measure:
      Positive Lead Measurement / Action Negative Lead
      C205-8
      GFD620822Courtesy of FORD MOTOR COMPANY
      		 C205-1

    Is the voltage greater than 11 volts? 

    Yes  GO to  C5
    No  REPAIR the circuit.

  6. C5 CHECK THE LIN (LOCAL INTERCONNECT NETWORK) CIRCUIT TO THE HEADLAMP SWITCH FOR AN OPEN

    • Ignition OFF.

    • Disconnect: BCM C2280B.

    • Measure:
      Positive Lead Measurement / Action Negative Lead
      C205-6
      GFD620821Courtesy of FORD MOTOR COMPANY
      		 C2280B-49

    Is the resistance less than 3 ohms? 

    Yes  GO to  C6
    No  REPAIR the circuit.

  7. C6 CHECK THE LIN (LOCAL INTERCONNECT NETWORK) CIRCUIT FOR A SHORT TO VOLTAGE

    • Ignition ON.

    • Measure:
      Positive Lead Measurement / Action Negative Lead
      C2280B-49
      GFD620822Courtesy of FORD MOTOR COMPANY
      		 Ground

    Is any voltage present? 

    Yes  REMOVE the fused jumper wire. REPAIR the circuit.
    No  REMOVE the fused jumper wire. GO to  C7

  8. C7 CHECK THE LIN (LOCAL INTERCONNECT NETWORK) CIRCUIT FOR A SHORT TO GROUND

    • Ignition OFF.

    • Measure:
      Positive Lead Measurement / Action Negative Lead
      C2280B-49
      GFD620821Courtesy of FORD MOTOR COMPANY
      		 Ground

    Is the resistance greater than 10, 000 ohms? 

    Yes  INSTALL a new headlamp switch. REFER to: Headlamp Switch . TEST the system for normal operation. If the low beams continue to illuminate, GO to  C14
    No  REPAIR the circuit.

  9. C8 CHECK FOR HCM (HEADLAMP CONTROL MODULE) DIAGNOSTIC TROUBLE CODE (DTCS)

    • Ignition ON.

    • Using a diagnostic scan tool, perform the HCM self-test.

    Is DTC B103C:01 or B103D:01 present? 

    Yes  GO to  C9
    No  GO to  C11

  10. C9 CHECK THE HEADLAMP INTERNAL HARNESS

    • Place the headlamp switch in the OFF position.

    • CHECK the internal headlamp harness for open or shorted circuits and damaged or pushed-out pins.

    Is the headlamp internal harness OK? 

    Yes  GO to  C10
    No  REPAIR the harness. If the harness cannot be repaired, INSTALL a new headlamp assembly. REFER to: Headlamp Assembly .

  11. C10 CHECK THE LED (LIGHT EMITTING DIODE) CONTROL MODULE

    • Connect: All disconnected connectors.

    • REMOVE the suspect headlamp LED control module.

    • Substitute the known good headlamp LED control module from the opposite headlamp.

    • Using the diagnostic scan tool, execute the LED Lamp Driver Initialization routine. Follow the diagnostic scan tool directions. CLEAR the Diagnostic Trouble Codes (DTCs) and REPEAT the self-test.

    • Place the headlamp switch in the HEADLAMPS position.

    Does the suspect headlamp operate correctly? 

    Yes  REMOVE the known good headlamp LED control module. INSTALL a new headlamp LED control module. REFER to: Light Emitting Diode (LED) Control Module . TEST the system for normal operation. If the condition still exists, INSTALL a new headlamp assembly. REFER to: Headlamp Assembly .
    No  REMOVE the known good headlamp LED control module. INSTALL a new headlamp assembly. 3to: Headlamp Assembly .

  12. C11 CHECK THE HCM (HEADLAMP CONTROL MODULE) LIN (LOCAL INTERCONNECT NETWORK) CIRCUIT FOR A SHORT TO VOLTAGE

    • Place the headlamp switch in the OFF position.

    • Ignition OFF.

    • Disconnect: HCM C2129.

    • Disconnect: LH Headlamp C1021A or RH Headlamp C1041A.

    • Ignition ON.

    • Measure:

      LH Headlamp 

      Positive Lead Measurement / Action Negative Lead
      C2129-10
      GFD620822Courtesy of FORD MOTOR COMPANY
      		 Ground

      RH Headlamp 

      Positive Lead Measurement / Action Negative Lead
      C2129-21
      GFD620822Courtesy of FORD MOTOR COMPANY
      		 Ground

    Is any voltage present? 

    Yes  REPAIR the circuit.
    No  GO to  C12

  13. C12 CHECK THE HCM (HEADLAMP CONTROL MODULE) LIN (LOCAL INTERCONNECT NETWORK) CIRCUIT FOR A SHORT TO GROUND

    • Ignition OFF.

    • Measure:

      LH Headlamp 

      Positive Lead Measurement / Action Negative Lead
      C2129-10
      GFD620821Courtesy of FORD MOTOR COMPANY
      		 Ground

      RH Headlamp 

      Positive Lead Measurement / Action Negative Lead
      C2129-21
      GFD620821Courtesy of FORD MOTOR COMPANY
      		 Ground

    Is the resistance greater than 10, 000 ohms? 

    Yes  GO to  C13
    No  REPAIR the circuit.

  14. C13 CHECK THE HCM (HEADLAMP CONTROL MODULE) LIN (LOCAL INTERCONNECT NETWORK) CIRCUIT FOR AN OPEN

    • Measure:

      LH Headlamp 

      Positive Lead Measurement / Action Negative Lead
      C2129-10
      GFD620821Courtesy of FORD MOTOR COMPANY
      		 C1021A-11

      RH Headlamp 

      Positive Lead Measurement / Action Negative Lead
      C2129-21
      GFD620821Courtesy of FORD MOTOR COMPANY
      		 C1041A-11

    Is the resistance less than 3 ohms? 

    Yes  GO to  C15
    No  REPAIR the circuit.

  15. C14 CHECK FOR CORRECT BCM (BODY CONTROL MODULE) OPERATION

    • Disconnect and inspect all BCM connectors.

    • Repair:

      • corrosion (install new connector or terminals - clean module pins)
      • damaged or bent pins - install new terminals/pins
      • pushed-out pins - install new pins as necessary

    • Reconnect the BCM connectors. Make sure they seat and latch correctly.

    • Operate the system and determine if the concern is still present.

    Is the concern still present? 

    Yes  CHECK OASIS for any applicable service articles: TSB, GSB, SSM or FSA. If a service article exists for this concern, DISCONTINUE this test and FOLLOW the service article instructions. If no service articles address this concern, INSTALL a new BCM. Refer to the appropriate Removal and Installation procedure in REMOVAL AND INSTALLATION
    No  The system is operating correctly at this time. The concern may have been caused by module connections. ADDRESS the root cause of any connector or pin issues.

  16. C15 CHECK FOR CORRECT HCM (HEADLAMP CONTROL MODULE) OPERATION

    • Disconnect and inspect the HCM connector.

    • Repair:

      • corrosion (install new connector or terminals - clean module pins)
      • damaged or bent pins - install new terminals/pins
      • pushed-out pins - install new pins as necessary

    • Reconnect the HCM connector. Make sure it seats and latches correctly.

    • Operate the system and determine if the concern is still present.

    Is the concern still present? 

    Yes  CHECK OASIS for any applicable Technical Service Bulletins (TSBs). If a TSB exists for this concern, DISCONTINUE this test and FOLLOW TSB instructions. If no Technical Service Bulletins (TSBs) address this concern, INSTALL a new HCM. REFER to: Headlamp Control Module (HCM) .
    No  The system is operating correctly at this time. The concern may have been caused by module connections. ADDRESS the root cause of any connector or pin issues.
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