Menu Icon
fall hauling headquarters

How to Add a Center Mounted Third Brake Light to a Trailer


I have a 2002 Nissan Xterra with a 4 wire flat connector. I want to add a third stop light to my trailer. This light has a second bulb for a running light and license plate light. The only success so far still makes the third stop flash when turn signals are applied. If I add a six wire converter to the truck how do I make the third light connect to brake? Thanks for any suggestions.

Expert Reply:

Although it is not required by law, what you are wanting to do is certainly possible.

Because trailer tail light systems combine the stop lamp and turn signals for each side onto a single circuit, you will need to use a vehicle-to-vehicle tail light converter, part # 118158 to split the brake light circuit back out.

The white wire on the input side of the converter would ground to the trailer frame, the green input wire would tap into the right turn circuit on the trailer and the yellow input wire would tap into the left turn circuit. The output side of the converter also has three wires. The yellow and green wires are not needed for this application, and could be cut short and should be capped off. The red wire would connect to your third stoplight, with the light also grounded to metal on the trailer frame.

Looking at the diagram I produced for you will give you a good idea of the wiring layout.

Click to Enlarge
expert reply by:
Michael L

Ask The Experts a Question >>

Products Referenced in This Question

Product Page this Question was Asked From

Similar Expert Q&A Pages

See More Q&A Expert Answers >>

About Us
photos and videos

Original Photos & Videos

Produced to make sure you know what you are getting and you get exactly what you need.


Installations Completed

To make sure products work and fit the way they are supposed to.

etrailer call center

Phone Calls & Emails Answered

1,125,924 phone calls and 1,350,587 emails to help find the right solution.

etrailer training

Average Hours of Product Training

We get to know our products firsthand so experts can better help you.

etrailer service

Years of Quality Customer Service

Assisting our neighbors and customers, face to face at the counter.

etrailer experts

Pages of Expert Information

Created to make sure you have all the answers to your questions, from real experts.