Troubleshooting Right Turn Signal/Brake Circuit on Trailer Towed By 2003 Dodge Ram 1500

Updated 06/15/2015 | Published 06/13/2015

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Peterson Combination Trailer Tail Light - 6 Function - Incandescent - Square - Passenger Side

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Hook Probe Circuit Tester

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Question:

I have a 2003 dodge 1500 truck. The driver side trailer lights are working and the passage side turn signal and brake light are not. We checked with the trailer connected and disconnected at the truck plug. Can you guys help me with trouble shooting this problem.

asked by: Harry T

Expert Reply:

The first thing you'll do is determine if the problem lies in the truck or the trailer wiring. Unplug the trailer, and have a helper activate the right turn signal. Use a circuit tester like part # PTW2993 to test the pin on the trailer connector for the right turn/brake signal.

If you get signal on that pin while the right turn signal is activated or the brake pedal is pressed, the problem lies in the trailer wiring. If you get no signal, you probably have a blown fuse. The tow package fuses can usually be found in the fuse box under the hood. The lid of the fuse box or the owner's manual will have a diagram showing which fuses protect which circuit. Locate the blown fuse and replace it. After replacing a fuse, examine trailer wiring as mentioned below.

If the problem is in the trailer wiring, you'll need to trace the right turn/brake lamp circuit from the trailer connector back to the lamp. Begin at the trailer connector, and examine the connector itself for corrosion or damage. Clean or replace if necessary. Continue tracing the circuit rearward, looking for pinched wires, loose connections or splices and cracked or worn wire insulation. Any of these can cause a short circuit.

I'll link you to some FAQ articles that I hope you'll find helpful.

expert reply by: Mike L