What Wire Does The Yellow Wire With Brown Stripe On My Trailer Connect To

Updated 07/11/2019 | Published 07/10/2019

Question:

I have a trailer harness with yellow wire with brown stripe. Does it get connected to the blue or brown on a flat 5 wire harness. Thanks

asked by: Tom A

Expert Reply:

On the trailer's 5-way connector the yellow wire with brown stripe is most likely a running light circuit but you want to be sure. There is sometimes a yellow/brown wire which is ran down the left side of the trailer for tail lights and a green/brown wire which is ran down the right side of the trailer for tail lights. Since wire color functions may vary depending on the manufacturer you still want to test the wire to determine the function by using a vehicle battery and jumper wire on the positive post. Touch the yellow wire to the jumper wire and see which function illuminates.

That wire will most likely connect to the brown wire on your 5-wire harness which is usually the tail light wire but you would to test it to be sure. The blue wire is usually an auxiliary wire on 5-way flats like part # A40W5B.

expert reply by: Heather A