What Does Trailer Wiring Converter Box do for Running Light Circuit

Updated 09/15/2025 | Published 08/28/2025

Question:

Curt 56400, 2022 nissan versa SR. I have power coming into the running lights wire But not on the other side going out to trailer. All the other functions work and I am tapped into the correct wire on the car for running lights. What exactly does the converter do? Can I just jumper the running lights across the converter to bypass that function? What feedback to the car should I expect? Ever heard of 1 function Not working while the others do? I have the same setup on my wifes identical car and everything works correctly? Tom

asked by: Tom L

Expert Reply:

Hey Tom, that is odd that the running light circuit of the Curt trailer wiring part # C56400 isn't working but when converter boxes fail they oftentimes do things like this.

For this circuit the converter box basically is just using the running light circuit of the vehicle as a signal wire and is drawing the power to light up the trailer lights for this circuit from the battery wire. So if you were to bypass the converter box for this circuit you'd be running the risk of shorting out the running light circuit of the vehicle. I wouldn't even consider this UNLESS your trailer has LED taillights since they draw a lot less.

expert reply by: Jameson C

Jameson C.

9/12/2025

Hey Tom, did you find a solution for the running lights issue with your Curt wiring harness? I'm curious because it could help others facing similar problems.