What is the Standard Wiring Color Code for a 4-Way Trailer Wiring System

Updated 01/04/2010 | Published 01/01/2010

Question:

my trailer lights come on with the lights .. but have no directionals or emergency flashers on the trailer. Please tell me which wires from the 4 wire system green, yellow, black and white ... should go from the pig tail connector to the lights thanks

asked by: Richard K

Expert Reply:

The standard for a 4-Pole trailer wiring system is as follows: white - ground, brown - tail/running lights, yellow - left turn and brake, green - right turn and brake.

You may want to use a circuit tester, like part # PTW2993, to make sure the vehicle connector is working properly. Often times bad ground connections can cause problems so check and make sure the ground wire on both the vehicle side and trailer side is attached to the metal frames, clear of paint and corrosion.

I have included a link to a wiring help page that has some diagrams and charts that may help you in trouble shooting your wiring problem.

expert reply by: Patrick B