Symptom Chart: Trailer Lamps

Diagnostics in this article assume a certain skill level and knowledge of Ford-specific diagnostic practices. Refer to Service Information for information regarding Ford-specific diagnostic practices.

Condition	Possible Sources	Actions
A module does not respond to the scan tool	Fuse Wiring, terminals or connectors Module	REFER to Module Communications Network .
All the trailer lamps are inoperative	Wiring, terminals or connectors Trailer tow connector Trailer concern	GO to Pinpoint Test AG .
One or more trailer stop/turn lamps are inoperative or always on	Fuse Wiring, terminals or connectors Trailer tow connector Trailer concern Trailer Module (TRM)	GO to Pinpoint Test AH .
The trailer parking lamps are inoperative or always on	Fuse Wiring, terminals or connectors Trailer tow connector Trailer concern Trailer tow parking lamps relay	GO to Pinpoint Test AI .
The trailer reversing lamps are inoperative or always on	Fuse Wiring, terminals or connectors Trailer tow connector Trailer concern Trailer tow reversing lamps relay	GO to Pinpoint Test AJ .
The trailer battery charging is inoperative/does not operate correctly	Fuse Wiring, terminals or connectors Trailer tow connector Trailer concern Trailer Module (TRM)	GO to Pinpoint Test AK .