Brake Wire Backfeeding to Light on 7-Way

Updated 04/10/2023 | Published 04/07/2023

Question:

Typical 7 pin trailer wiring, no electric brakes or aux power. Good ground. One light for turn signal and brake on each side. I connect the ground and running lights to their designated wire on the light. But when I combine the brake and turn signal wires together and attach to the last wire for the right light the left light turns on. I found out there is current back feeding through the brake wire to the left light. What am I doing wrong ?

asked by: Dan R

Expert Reply:

It doesn't sound like you are doing anything wrong from what I can tell. Based on how you are describing it with the backfeed, a diode may be the solution on that brake wire to help isolate the power. For that use the Roadmaster Single Park Light Diode # RM-690.

expert reply by: Kyle S