Recommended Trailer Wiring for 7-Way with Only 5 Wires

Updated 01/08/2018 | Published 01/06/2018

Products Featured in This Question

Ring Terminal - 12-10 Gauge Wire - 3/16" Ring ID

(72)

$1.20

Hook Probe Circuit Tester

(67)

$14.32

Question:

Utility trailer with brakes. Harness is a 7 pin type, but only 5 wires coming in, Black, green and yellow from light? Then a white and black that goes to the brakes. Plugging into my truck, which works with all other trailers I have, light work, brakes work, but when put on flashers, lights go off. What are the proper terminals for the 5 wires? Thank! You guys and gals are the best!!

asked by: Mike E

Expert Reply:

I've attached a diagram for you with function locations. Your left turn and stop are what will need to be connected for the flashers to work. These are found on the left and right side blades of your 7-way connectors. I recommend using a circuit tester like # PTW2993 to check your wiring functions on your lights. It sounds like you have a running/parking light, turn signal/stop, and ground but the colors are not typical.

My recommendation because your wiring colors are not standard is to use the Epicord 7-Way Molded Trailer Plug with Junction Box - 10' Long # 277-000141 to help you with isolate the functions and assist with future troubleshooting as needed. This will also give you a molded 7-way connector and box to ensure your connections are well protected. You can use # 44-5310A for ring terminals on these posts.

expert reply by: Jason S