Troubleshooting Running Light Circuit on Trailer
Question:
I have a trailer with basic 4 wire flat plug, the plug i removed had 5 wires, two brown wires attached to one terminal on the flat plug, I installed new wiring and lights, connected them to a new 4 prong flat plug, I have turn signal and break lights on both sides but no running lights on eather side, I connected the brown wires from each light together and to the brown wire on the flat plug. i have checked all connections and wires with an ohm meter and they are good? any thoughts? Regards
asked by: John
Expert Reply:
I would begin by testing the trailer connector on the vehicle to rule that out. Turn the headlights on, and use a circuit tester like part # 40376 to test the socket on the connector fed by the brown wire. If you are not getting a signal on this pin, you might have a blown fuse.
Make sure the ground wire from the connector on the trailer is securely grounded to the trailer frame and that each lamp is grounded to the trailer frame either by an individual ground wire connected to the trailer frame or by its mounting studs being in metal to metal contact with the trailer frame. Some trailers use a plastic license plate bracket sandwiched between the drivers side tail light and the trailer frame. The plastic frame can prevent a good ground connection, a ground wire should be ran from the mounting stud to the trailer frame.
Although you have already checked the connections on the running light circuit, they are worth checking again. Make sure you have a continuous circuit from the trailer connector to the lamps, with each wiring connection being secure and protected from the elements.
Products Referenced in This Question
4-Way Flat Trailer Connector w/ 60" Harness and Wire Taps
- Trailer Wiring
- Trailer Connectors
- Vehicle End Connector
- 0 - 5 Feet Long
- Plug and Lead
- 4 Flat
- Tekonsha
more information >
Product Page this Question was Asked From
4-Way Flat Trailer Connector w/ 60" Harness and Wire Taps
- Trailer Wiring
- Trailer Connectors
- Vehicle End Connector
- 0 - 5 Feet Long
- Plug and Lead
- 4 Flat
- Tekonsha
more information >
Featured Help Information
Miscellaneous Media
Continue Researching
- Shop: Trailer Hitch
- Shop: EcoHitch Hidden Trailer Hitch Receiver - Custom Fit - Class III - 2"
- Shop: Trailer Wiring
- Shop: Mounting Bracket 4-Pole Flat
- Shop: EcoHitch Hidden Trailer Hitch Receiver - Custom Fit - 2"
- Video: Tow Ready 4-Pole Mounting Bracket Installation
- Shop: Curt T-Connector Vehicle Wiring Harness with 4-Pole Flat Trailer Connector
- Article: Routing the Power Wire for a Trailer Wiring Harness
- Shop: T-One Vehicle Wiring Harness with 4-Pole Flat Trailer Connector
- Article: Trailer Wiring Diagrams
- Article: Troubleshooting 4 and 5-Way Wiring Installations
- Video: EcoHitch Class III Hidden Trailer Hitch Installation - 2023 Volkswagen Tiguan
- Video: Choosing the Right Trailer Wiring
- Q&A: Troubleshooting Curt T-Connector # C56403 With Power Always On Green Wire/Right Trailer Light
- Video: Curt T-Connector Vehicle Wiring Harness Installation - 2018 Volkswagen Tiguan
- Video: Curt T-Connector Vehicle Wiring Harness Installation - 2021 Volkswagen Tiguan
- Shop: Bauer Products 4-Way Trailer Plug Holder
- Shop: Curt Mounting Bracket for 4-Pole Flat Trailer Connector
- Q&A: How To Run the Power Wire for the Curt T-Connector on a 2019 Volkswagen Tiguan
- Q&A: What Should the Voltage Output Be at the 4-Way Plug on Curt T-Connector Wiring Harness # 56016
- Q&A: How to Test a 4-Way Trailer Wiring Harness Plug
- Q&A: Both Blinkers on With Wiring Harness 118811
- Q&A: Is The Curt 4-Way # C56403 Better Or Worse Than The Tekonsha 4-Way # 118811 On a 2022 VW Tiguan?
- Q&A: Troubleshooting Curt Trailer Wiring Harness and Adapter Installation
- Article: Brake Controller 7- and 4-Way Installation Kit (ETBC7)
- Search Results: 44649
- Video: Choosing the Right Brake Controller
- Search Results: 68149
- Article: How to Choose the Right Trailer Hitch Class
- Search Results: 25580
on Trailer Wiring
