How to Wire Up New Trailer Lights When Wiring Colors are Unknown

Updated 03/14/2016 | Published 03/11/2016

Question:

I have new lights for my trailer and the new lights have 2wireswhich has 4 wires which are white black red yellow and other has black white brown and white the lead to my trailor has got blue white brown green red yellow black what goes to what

asked by: Stephen

Expert Reply:

Since trailer wiring doesn't always abide by the typical wiring color standards I won't be able to tell you exactly where everything needs to go but I can help you figure it all out.

Sounds like you have a 7-way on your trailer and the colors for it are standard. Meaning blue is brake output, white is ground, brown is taillight, green is right turn/stop, red is reverse light, and black is 12 volt accessory. I attached a diagram that should help with that.

Since I don't know what lights you have all I can say is that most likely the white wire is ground and the rest will have to be tested to determine which are what. Use a jumper wire from a 12 volt battery to see which circuits illuminate and wire them to the wiring accordingly.

expert reply by: Jameson C