Symptom Chart

WARNING: This page is about a different car, the 2013 Ford F-550 Super Duty, 2013 Ford F-450 Super Duty, 2013 Ford F-350 Super Duty, and 2013 Ford F-250 Super Duty. However, it is still accessible from the selected car via links, so may be relevant.

SYMPTOM CHART

Condition	Possible Sources	Action
All the trailer lamps are inoperative	Wiring, terminals or connectors Trailer tow connector Trailer	GO to PINPOINT TEST X .
The trailer stop/turn lamp is inoperative	Fuse Wiring, terminals or connectors Trailer tow connector Trailer tow stop/turn relay Trailer	GO to PINPOINT TEST Y .
The trailer parking lamps are inoperative	Fuse Wiring, terminals or connectors Trailer tow connector Trailer tow parking lamp relay Trailer	GO to PINPOINT TEST Z .
The trailer reversing lamps are inoperative	Fuse Wiring, terminals or connectors Trailer tow connector Trailer tow reversing lamp relay Trailer	GO to PINPOINT TEST AA .
The trailer lamps are on continuously	Wiring, terminals or connectors Trailer tow relay Trailer	GO to PINPOINT TEST AB .
The trailer battery charging is inoperative/does not operate correctly	Fuse Wiring, terminals or connectors Trailer tow connector Trailer tow battery charge relay Trailer	GO to PINPOINT TEST AC .
The trailer electric brakes are inoperative/always applied	Fuse Wiring, terminals or connectors Trailer tow connector Trailer Brake Control (TBC) module (aftermarket) Trailer Body Control Module (BCM)	GO to PINPOINT TEST AD .