Pinpoint Test E : The Trailer Reversing Lamps Are Inoperative Or Always On

WARNING: This page is about a different car, the 2018 Lincoln Navigator. However, it is still accessible from the selected car via links, so may be relevant.

E1 CHECK FOR VOLTAGE THROUGH THE TRAILER TOW CONNECTOR

Ignition OFF.

Disconnect: Trailer.

Apply the parking brake.

Ignition ON.

Place the gear selector lever in REVERSE.

Measure:

Positive Lead	Measurement / Action	Negative Lead
7-Pin Connector, Pin 7	Courtesy of FORD MOTOR COMPANY	Ground

Place the gear selector lever in PARK.

Measure:

Positive Lead	Measurement / Action	Negative Lead
7-Pin Connector, Pin 7	Courtesy of FORD MOTOR COMPANY	Ground

Is the voltage greater than 11 volts when the gear selector lever is in REVERSE and 0 volts when the gear selector lever is in PARK?

Yes	The vehicle is operating correctly. SEND the trailer to an authorized camper/trailer repair facility.

No	If the trailer reversing lamps are inoperative, GO to E2If the trailer reversing lamps are always on, GO to E8

E2 CHECK FOR VOLTAGE TO THE TRAILER TOW CONNECTOR (VEHICLE HARNESS)

Place the gear selector lever in PARK.

Ignition OFF.

Disconnect: Trailer Tow C4099 .

Apply the parking brake.

Ignition ON.

Place the gear selector lever in REVERSE.

Measure:

Positive Lead	Measurement / Action	Negative Lead
C4099-7	Courtesy of FORD MOTOR COMPANY	Ground

Is the voltage greater than 11 volts?

Yes	INSTALL a new trailer tow connector. TEST the system for normal operation.

No	VERIFY the BJB fuse 74 (10A) is OK. If OK, GO to E3 If not OK, Refer to the Wiring Diagram Information to identify the possible causes of the circuit short.

E3 CHECK THE TRAILER TOW REVERSING LAMPS RELAY ENERGIZE CIRCUIT FOR VOLTAGE

Place the gear selector lever in PARK.

Ignition OFF.

NOTE: To access the BJB connectors, the bottom cover of the BJB must be removed.

Disconnect: BJB C1035C .

Apply the parking brake.

Ignition ON.

Place the gear selector lever in the REVERSE.

Measure:

Positive Lead	Measurement / Action	Negative Lead
C1035C-26	Courtesy of FORD MOTOR COMPANY	Ground

Is the voltage greater than 11 volts?

Yes

GO to E4

GO to E5

E4 CHECK THE TRAILER TOW REVERSING LAMPS RELAY GROUND CIRCUIT

Place the gear selector lever in PARK.

Ignition OFF.

NOTE: To access the BJB connectors, the bottom cover of the BJB must be removed.

Disconnect: BJB C1035B .

Apply the parking brake.

Ignition ON.

Place the gear selector lever in the REVERSE.

Measure:

Positive Lead	Measurement / Action	Negative Lead
C1035C-26	Courtesy of FORD MOTOR COMPANY	C1035B-42

Is the voltage greater than 11 volts?

Yes

GO to E7

No	REPAIR the circuit.

E5 CHECK THE TRAILER TOW REVERSING LAMPS RELAY ENERGIZE CIRCUIT FOR A SHORT TO GROUND

Place the gear selector lever in PARK.

Ignition OFF.

Disconnect: BCM C2280G .

Measure:

Positive Lead	Measurement / Action	Negative Lead
C2280G-19	Courtesy of FORD MOTOR COMPANY	Ground

Is the resistance greater than 10, 000 ohms?

Yes

GO to E6

No	REPAIR the circuit.

E6 CHECK THE TRAILER TOW REVERSING LAMPS RELAY ENERGIZE CIRCUIT FOR AN OPEN

Measure:

Positive Lead	Measurement / Action	Negative Lead
C2280G-19	Courtesy of FORD MOTOR COMPANY	C1035C-26

Is the resistance less than 3 ohms?

Yes

GO to E11

No	REPAIR the circuit.

E7 CHECK THE TRAILER TOW REVERSING LAMPS RELAY OUTPUT CIRCUIT FOR AN OPEN

NOTE: To access the BJB connectors, the bottom cover of the BJB must be removed.

Disconnect: BJB C1035D .

Measure:

Positive Lead	Measurement / Action	Negative Lead
C4099-7	Courtesy of FORD MOTOR COMPANY	C1035D-24

Is the resistance less than 3 ohms?

Yes	INSTALL a new BJB.

No	REPAIR the circuit.

E8 CHECK THE TRAILER TOW REVERSING LAMPS RELAY OUTPUT CIRCUIT FOR A SHORT TO VOLTAGE

Place the headlamp switch in the OFF position.

Ignition OFF.

NOTE: To access the BJB connectors, the bottom cover of the BJB must be removed.

Disconnect: BJB C1035D .

Ignition ON.

Measure:

Positive Lead	Measurement / Action	Negative Lead
C4099-7	Courtesy of FORD MOTOR COMPANY	Ground

Is any voltage present?

Yes	REPAIR the circuit.

GO to E9

E9 CHECK THE TRAILER TOW REVERSING LAMPS RELAY ENERGIZE CIRCUIT FOR VOLTAGE IN PARK

Place the gear selector lever in PARK.

Ignition OFF.

Disconnect: BJB C1035C .

Ignition ON.

Measure:

Positive Lead	Measurement / Action	Negative Lead
C1035C-26	Courtesy of FORD MOTOR COMPANY	Ground

Is any voltage present?

Yes

GO to E10

No	INSTALL a new BJB.

E10 CHECK THE TRAILER TOW REVERSING LAMPS RELAY ENERGIZE CIRCUIT FOR A SHORT TO VOLTAGE

Ignition OFF.

Disconnect: BCM C2280G .

Ignition ON.

Measure:

Positive Lead	Measurement / Action	Negative Lead
C1035C-26	Courtesy of FORD MOTOR COMPANY	Ground

Is any voltage present?

Yes	REPAIR the circuit.

GO to E11

E11 CHECK FOR CORRECT BCM (BODY CONTROL MODULE) OPERATION

Disconnect and inspect all BCM and all related in-line 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 and all related in-line 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, BCM guided routine is not applicable for this vehicle and market. Replace the component that was faulted through service information diagnosis.

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.