Does Brown on Trailer Wiring Indicate Running Light Circuit

Published 10/07/2015

Question:

My trailer has lights that are wired red and brown, I presume this is blinkerred and running lightsbrown. The way its wired now there are 3 sets of black and white wires, one for left, one for right, and one for... brakes? the 3rd black and white wire pair appears to go to a set of drums on the wheels. I have no idea what to do with that. Im willing to ignore for the moment, but any insight would be appreciated. I want to replace all the black and white wiring with the 4 color green, yellow, brown, white wire. My first impression was that I would have a ground coming from each light that I would twist in with the white ground of the harness, that doesnt appear to be the case. With only 2 wires red and brown from each light it seems like I should be going brown to brown, right red to green, left red to yellow, and grounding to the chassis somehow. Please tell me Im making sense.

asked by: John F

Expert Reply:

Most likely the trailer light wiring you have on your trailer that have brown on them are for the running light circuit and the ones with red are for stop/turn circuits.

Your best option is to test the wires with a circuit tester like part # 3808 while a buddy applies the trailer light functions and then wire your trailer accordingly.

expert reply by: Jameson C