Troubleshooting Trailer Wiring Install Where Wire Sparks When Connected to Running Lights

Updated 07/29/2021 | Published 07/28/2021

Products Featured in This Question

35 Ft 4-Way Trailer Wiring Harness - Wishbone Style - 42" Ground

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$26.15

Hook Probe Circuit Tester

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$12.94

Question:

2019 Honda Odessy is the pull vehicle. 4 wire plug. The red running lights and side markers are grounded via the mounting screws. I plan on connecting the running lights to the left brown wire. When I connect the lights to a quad battery 12 volt, everything is ok except for the red running lights. The wires spark when connected similar to the other lights. My thought is I pinched the wire when going thru the medal frame of the trailer. Any thoughts. I plan on trying to only splice the wires on the left side just about where the wires come out of the plastic cover and then them into a plastic cover and run they to the other side of the trailer. Sorry about the NY picture. I was not able to it and I did not want to loose everything!

asked by: John J

Expert Reply:

Since you are seeing a spark when connecting the running light circuit to the other wiring that would indicate that the wire you are trying to connect to is a ground wire or is in some way grounding to the trailer. Have you put a circuit tester like the part # PTW2993 on the wire you are trying to connect to see if there's voltage on it? I think your guess is correct most likely that somewhere on that wire it has exposed wire touching the trailer frame and fixing that would take care of the problem.

expert reply by: Jameson C