How to Determine Functions of Different Colored Trailer Wires

Question:

White green brown yellow need to know how to match red brown blue black

asked by: Rickey

Expert Reply:

The Hopkins 4-way connector, part # HM48205, uses white for ground, brown for the running lights, green for right side (passenger) turn signals and brake lights, and yellow for left side (driver) turn signals and brake lights. This is the standard wire coloring for trailer wiring, but just because it's standard doesn't make it law.

To match the Hopkins up to your wires you're going to need to find out what each color does because there isn't anything to tell us. on the vehicle side you can use a circuit tester, like part # PTW2993, and test each wire as you're engaging each function. The trailer side is a little trickier because you need to supply power to it. Use a charged 12-volt battery and ground the negative post. Then touch each of your wires to the positive side, one by one, and see which function engages.

expert reply by: Charles S