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PINPOINT TEST AI : The Trailer Stop-Turn Lamps Are Inoperative

  1. AI1 VERIFY THE TRAILER LAMP OPERATION

    • Ignition OFF.
    • Determine if both trailer stop/turn lamps are inoperative.

    Are both trailer stop/turn lamps inoperative? 

    Yes  VERIFY the BJB fuse 63 (15A) is OK. If OK, REPAIR the trailer stop/turn lamp relay voltage supply circuit for an open. If not OK, REFER to the OEM ELECTRICAL WIRING DIAGRAM INTRODUCTION to identify the possible causes of the circuit short.
    No  For an inoperative left trailer stop/turn lamp, GO to  AI2. For an inoperative right trailer stop/turn lamp, GO to  AI11.

  2. AI2 CHECK FOR VOLTAGE THROUGH THE TRAILER TOW CONNECTOR (LEFT TRAILER STOP/TURN LAMP)

    • For the 4-pin connector, while applying the brake pedal, measure:
      Positive Lead Measurement / Action Negative Lead
      C439-2
      GFD33595Courtesy of FORD MOTOR COMPANY
      		 Ground
    • For the 7-pin connector, while applying the brake pedal, measure:
      Positive Lead Measurement / Action Negative Lead
      Trailer Tow Connector Pin 1
      GFD33595Courtesy of FORD MOTOR COMPANY
      		 Ground

    Is the voltage greater than 11 volts? 

    Yes  The vehicle is operating correctly. SEND the trailer to an authorized camper/trailer repair facility.
    No  For the 4-pin connector, GO to  AI4. For the 7-pin connector, GO to  AI3.

  3. AI3 CHECK FOR VOLTAGE TO THE TRAILER TOW CONNECTOR (LEFT STOP/TURN 7- PIN)

    • Disconnect: Trailer Tow Connector.
    • While applying the brake pedal, measure:
      Positive Lead Measurement / Action Negative Lead
      C4099-1
      GFD33595Courtesy of FORD MOTOR COMPANY
      		 Ground

    Is the voltage greater than 11 volts? 

    Yes  INSTALL a new trailer tow connector.
    No  GO to  AI4.

  4. AI4 CHECK THE TRAILER TOW LEFT STOP/TURN RELAY

    • Disconnect: Trailer Tow Left Stop/Turn Relay.
    • Substitute a known good relay.
    • For the 4-pin connector, while applying the brake pedal, measure:
      Positive Lead Measurement / Action Negative Lead
      C439-2
      GFD33595Courtesy of FORD MOTOR COMPANY
      		 Ground
    • For the 7-pin connector, while applying the brake pedal, measure:
      Positive Lead Measurement / Action Negative Lead
      C4099-1
      GFD33595Courtesy of FORD MOTOR COMPANY
      		 Ground

    Is the voltage greater than 11 volts? 

    Yes  REMOVE the known good relay. INSTALL a new trailer tow turn relay.
    No  REMOVE the known good relay. GO to  AI5.

  5. AI5 CHECK FOR VOLTAGE TO THE TRAILER TOW LEFT STOP/TURN LAMP RELAY COIL

    • While applying the brake pedal, measure:
      Positive Lead Measurement / Action Negative Lead
      Trailer Tow Left Stop/Turn Relay Pin 2
      GFD33595Courtesy of FORD MOTOR COMPANY
      		 Ground

    Is the voltage greater than 11 volts? 

    Yes  GO to  AI6.
    No  GO to  AI8.

  6. AI6 CHECK THE TRAILER TOW LEFT STOP/TURN LAMP RELAY BJB VOLTAGE SUPPLY CIRCUIT FOR AN OPEN

    • Measure:
      Positive Lead Measurement / Action Negative Lead
      Trailer Tow Left Stop/Turn Relay Pin 3
      GFD33595Courtesy of FORD MOTOR COMPANY
      		 Ground

    Is the voltage greater than 11 volts? 

    Yes  GO to  AI7.
    No  REPAIR the circuit.

  7. AI7 CHECK THE TRAILER TOW LEFT STOP/TURN LAMP RELAY GROUND CIRCUIT FOR AN OPEN

    • Measure:
      Positive Lead Measurement / Action Negative Lead
      Trailer Tow Left Stop/Turn Relay Pin 3
      GFD37128Courtesy of FORD MOTOR COMPANY
      GFD33595Courtesy of FORD MOTOR COMPANY
      		 Trailer Tow Left Stop/Turn Relay Pin 1
      GFD37128Courtesy of FORD MOTOR COMPANY

    Is the voltage greater than 11 volts? 

    Yes  REPAIR the trailer tow left stop/turn relay output circuit to the trailer tow connector for an open.
    No  REPAIR the trailer tow left stop/turn relay ground circuit for an open.

  8. AI8 PERFORM THE BCM SELF-TEST AND RECHECK FOR VOLTAGE TO THE TRAILER TOW LEFT STOP/TURN LAMP RELAY COIL

    • Ignition ON.
    • Using a scan tool, perform the BCM on-demand self-test.
    • While applying the brake pedal, measure:
      Positive Lead Measurement / Action Negative Lead
      Trailer Tow Left Stop/Turn Relay Pin 2
      GFD33595Courtesy of FORD MOTOR COMPANY
      		 Ground

    Is the voltage greater than 11 volts? 

    Yes  INSTALL a new trailer tow turn relay.
    No  GO to  AI6.

  9. AI9 CHECK THE TRAILER TOW LEFT STOP/TURN LAMP RELAY COIL VOLTAGE SUPPLY CIRCUIT FOR A SHORT TO GROUND

    • Ignition OFF.
    • Disconnect: BCM C2280D.
    • Measure:
      Positive Lead Measurement / Action Negative Lead
      Trailer Tow Left Stop/Turn Relay Pin 2
      GFD33596Courtesy of FORD MOTOR COMPANY
      		 Ground

    Is the resistance greater than 10, 000 ohms? 

    Yes  GO to  AI10.
    No  REPAIR the circuit.

  10. AI10 CHECK THE TRAILER TOW LEFT STOP/TURN LAMP RELAY COIL VOLTAGE SUPPLY CIRCUIT FOR AN OPEN

    • Measure:
      Positive Lead Measurement / Action Negative Lead
      Trailer Tow Left Stop/Turn Relay Pin 2
      GFD33596Courtesy of FORD MOTOR COMPANY
      		 C2280D-12

    Is the resistance less than 3 ohms? 

    Yes  GO to  AI20.
    No  REPAIR the circuit.

  11. AI11 CHECK FOR VOLTAGE THROUGH THE TRAILER TOW CONNECTOR (RIGHT TRAILER STOP/TURN LAMP)

    • For the 4-pin connector, while applying the brake pedal, measure:
      Positive Lead Measurement / Action Negative Lead
      C439-1
      GFD33595Courtesy of FORD MOTOR COMPANY
      		 Ground
    • For the 7-pin connector, while applying the brake pedal, measure:
      Positive Lead Measurement / Action Negative Lead
      Trailer Tow Connector Pin 4
      GFD33595Courtesy of FORD MOTOR COMPANY
      		 Ground

    Is the voltage greater than 11 volts? 

    Yes  The vehicle is operating correctly. SEND the trailer to an authorized camper/trailer repair facility.
    No  For the 4-pin connector, GO to  AI13. For the 7-pin connector, GO to  AI12.

  12. AI12 CHECK FOR VOLTAGE TO THE TRAILER TOW CONNECTOR (RIGHT STOP/TURN 7- PIN)

    • Disconnect: Trailer Tow Connector.
    • While applying the brake pedal, measure:
      Positive Lead Measurement / Action Negative Lead
      C4099-4
      GFD33595Courtesy of FORD MOTOR COMPANY
      		 Ground

    Is the voltage greater than 11 volts? 

    Yes  INSTALL a new trailer tow connector.
    No  GO to  AI13.

  13. AI13 CHECK THE TRAILER TOW RIGHT STOP/TURN RELAY

    • Disconnect: Trailer Tow Right Stop/Turn Relay.
    • Substitute a known good relay.
    • For the 4-pin connector, while applying the brake pedal, measure:
      Positive Lead Measurement / Action Negative Lead
      C439-1
      GFD33595Courtesy of FORD MOTOR COMPANY
      		 Ground
    • For the 7-pin connector, while applying the brake pedal, measure:
      Positive Lead Measurement / Action Negative Lead
      C4099-4
      GFD33595Courtesy of FORD MOTOR COMPANY
      		 Ground

    Is the voltage greater than 11 volts? 

    Yes  REMOVE the known good relay. INSTALL a new trailer tow turn relay.
    No  REMOVE the known good relay. GO to  AI14.

  14. AI14 CHECK FOR VOLTAGE TO THE TRAILER TOW RIGHT STOP/TURN LAMP RELAY COIL

    • While applying the brake pedal, measure:
      Positive Lead Measurement / Action Negative Lead
      Trailer Tow Right Stop/Turn Relay Pin 2
      GFD33595Courtesy of FORD MOTOR COMPANY
      		 Ground

    Is the voltage greater than 11 volts? 

    Yes  GO to  AI15.
    No  GO to  AI17.

  15. AI15 CHECK THE TRAILER TOW RIGHT STOP/TURN LAMP RELAY BJB VOLTAGE SUPPLY CIRCUIT FOR AN OPEN

    • Measure:
      Positive Lead Measurement / Action Negative Lead
      Trailer Tow Right Stop/Turn Relay Pin 3
      GFD33595Courtesy of FORD MOTOR COMPANY
      		 Ground

    Is the voltage greater than 11 volts? 

    Yes  GO to  AI16.
    No  REPAIR the circuit.

  16. AI16 CHECK THE TRAILER TOW RIGHT STOP/TURN LAMP RELAY GROUND CIRCUIT FOR AN OPEN

    • Measure:
      Positive Lead Measurement / Action Negative Lead
      Trailer Tow Right Stop/Turn Relay Pin 3
      GFD37129Courtesy of FORD MOTOR COMPANY
      GFD33595Courtesy of FORD MOTOR COMPANY
      		 Trailer Tow Right Stop/Turn Relay Pin 1
      GFD37129Courtesy of FORD MOTOR COMPANY

    Is the voltage greater than 11 volts? 

    Yes  REPAIR the trailer tow right stop/turn relay output circuit to the trailer tow connector for an open.
    No  REPAIR the trailer tow right stop/turn relay ground circuit for an open.

  17. AI17 PERFORM THE BCM SELF-TEST AND RECHECK FOR VOLTAGE TO THE TRAILER TOW RIGHT STOP/TURN LAMP RELAY COIL

    • Ignition ON.
    • Using a scan tool, perform the BCM on-demand self-test.
    • While applying the brake pedal, measure:
      Positive Lead Measurement / Action Negative Lead
      Trailer Tow Right Stop/Turn Relay Pin 2
      GFD33595Courtesy of FORD MOTOR COMPANY
      		 Ground

    Is the voltage greater than 11 volts? 

    Yes  INSTALL a new trailer tow turn relay.
    No  GO to  AI18.

  18. AI18 CHECK THE TRAILER TOW RIGHT STOP/TURN LAMP RELAY COIL VOLTAGE SUPPLY CIRCUIT FOR A SHORT TO GROUND

    • Ignition OFF.
    • Disconnect: BCM C2280D.
    • Measure:
      Positive Lead Measurement / Action Negative Lead
      Trailer Tow Right Stop/Turn Relay Pin 2
      GFD33596Courtesy of FORD MOTOR COMPANY
      		 Ground

    Is the resistance greater than 10, 000 ohms? 

    Yes  GO to  AI19.
    No  REPAIR the circuit.

  19. AI19 CHECK THE TRAILER TOW LEFT STOP/TURN LAMP RELAY COIL VOLTAGE SUPPLY CIRCUIT FOR AN OPEN

    • Measure:
      Positive Lead Measurement / Action Negative Lead
      Trailer Tow Right Stop/Turn Relay Pin 2
      GFD33596Courtesy of FORD MOTOR COMPANY
      		 C2280D-15

    Is the resistance less than 3 ohms? 

    Yes  GO to  AI20.
    No  REPAIR the circuit.

  20. AI20 CHECK FOR CORRECT BCM 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 TSBs. If a TSB exists for this concern, DISCONTINUE this test and FOLLOW TSB instructions. If no TSBs address this concern, INSTALL a new BCM. REFER to Multifunction Electronic Modules - Without Intelligent Access or REFER to Multifunction Electronic Modules - With Intelligent Access .
    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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