How to Test a Trailer Wiring Harness Converter to See if it Needs to be Replaced

Question:

I have plugged in both t-connectors, I have made sure the ground is attached, I have veified that both right and left turn signals work and the running lights work as well but there is no power to the brake lights. I have checked them all with a test light as well as plugging them into my new trailer. I am guessing the the black converter box that is supposed to combine the car brake and turn signals into 1 wire is not working correctly. I would like any further trouble shooting advice you may have or if you agree then I need to know how to send the t-connector/wireing harness back to you for replacement. car info 2014 Nissan Juke 4 door, front wheel drive wire harness part # C56124 Thanks,

asked by: Jon H

Expert Reply:

It sounds like the box is at fault, but you can verify this by testing the input side of the box on the stoplight circuit wire (red) and then testing the output wires for the yellow and green wire of the 4-way.

If there is voltage going into the converter box on the red wire when the brakes are applied but none are coming out then the box is bad and needs to be replaced. If there is no voltage going into the box then that wire isn't connecting to the correct circuit on your vehicle. You can try reconnecting the connector to make sure it is making proper contact.

expert reply by: Jameson C