Troubleshooting My 4-Way Connector Because My Trailer Lights Not Working

Published 02/16/2022

Question:

10 fj cruiser, factory trailer lighting, 4 flat, all the lights work on the truck and all the lights work on the trailer, except the tail/ running lights. Ive checked trailer lights with a batt and jumpers all work fine. I have pwr,12v,on all truck plug pins except the tail light pin, it only has 5/6 volts. What can I check next?

asked by: Andy D

Helpful Expert Reply:

I would double check the ground on your 2010 Toyota FJ Cruiser. It appears that you have gone through all of our recommended steps when you are missing one function on your trailer's lights, in this case the tail lights/running lights. The steps are as follows:

1, You will be circuit testing the 4-way plug and behind the converter box with a circuit tester, part # PTW2992 .
2. Verify the correct wire connections, the hardware and the wires.
3. Checking the ground wires on the tow vehicle and on the trailer. I would pay close attention to any paint, corrosion, or buildup where the ground is connected.
4. Finding other possible issues.
5. Checking for an overload situation.

I have included a product description link, a video review link, and a weblink for troubleshooting 4-way connectors.

expert reply by: Mark Smith