Trailer Light Wire Functions and Installing a 4-Way Harness on a Trailer
Question:
hi i have a small trailer that only has three wires for the lights and i want to put on a four flat trailer adapter the colors from the trailer lights are black white and green.could u tell me how this conects .do i have to double somthing up?
asked by: Joe
Expert Reply:
Trailer lights have combined brake and turn signal circuits, a running light circuit, and a ground. Most likely, the black wire on your light is for the running lights, green is for stop and turn, and white is ground. Use a circuit tester like # 3808 if needed to confirm the wire functions.
On a harness like # 18004, you will need to have a jumper wire (basically split) the brown running light circuit to go to each side of the trailer. The other option is to use a wishbone harness, # A35W42B. This harness has the running light circuit split at the connector so you do not need to split the running light circuit. I have included a link to a video showing a typical installation.
Products Referenced in This Question
35 Ft 4-Way Trailer Wiring Harness - Wishbone Style - 42" Ground
- Trailer Wiring
- Trailer Connectors
- Trailer End Connector
- 31 Feet and Longer
- Plug and Lead
- 4 Flat
- Optronics
more information >
Product Page this Question was Asked From
- Trailer Wiring
- Trailer Connectors
- Trailer End Connector
- 0 - 5 Feet Long
- Plug and Lead
- 4 Flat
- Draw-Tite
more information >
Continue Researching
- Q&A: Lippert Crank Handle for Lippert Spare Tire Winch Assembly
- Q&A: Inside Diameter of Replacement Crank Extension for Lippert Spare Tire Winch Assemblies
- Q&A: How Does Lippert Components Spare Tire Winch with Offset Cable Crank Up and Down
- Q&A: Does Lippert Spare Tire Winch Lock or Hold in Any Position?
- Q&A: How Does the Handle Work on the Lippert Components Spare Tire Winch 159056
- Q&A: How is Lippert Spare Tire Winch LC159056 Raised and Lowered
- Q&A: Can Bearing Buddy Bearing Protectors Be Over-Filled with Too Much Grease
- Article: Trailer Wiring Diagrams
- Article: Testing Trailer Brake Magnets for Proper Function
- Article: How to Measure for Travel Trailer and Fifth Wheel Steps
- Article: How to Measure for Trailer Hitch Drop
- Article: Trailer Tire Sizing
- Article: Brake Controller Installation: Starting from Scratch
- Article: Towing a Trailer? Let's Talk About Brake Controllers