How to Wire New 7 Way Trailer Connector With Junction Box

Question:

My trailer is wired for a 4-way connection. I have already installed the ETBC7 Universal Installation kit and a brake controller. I am adding electric brakes to my trailer. My question is - since I already have a 4 way connection on the trailer side and the only addition is the electric brakes, do I only need to connect the Brake Wire hot lead to this junction box? Assuming I can just plug the existing 4 way that covers the trailer brake lights and turn signals. Thank you.

asked by: Dylan K

Expert Reply:

Long story short, you can wire your brakes and 12v auxiliary charge line into the junction box on the Epicord 7 Way # 277-000141 and continue to use the 4 way connector. With that being said, there is a much cleaner and more practical way to do this.

You can start by cutting off the 4 way connector on your trailer and then wiring those wires into the junction box on the Epicord. Once you've wired those in, you'll run the brake wires from your trailer brakes into the junction box, as well as the 12v auxiliary charge line to complete the 7 way connection and allow all of the signals to travel from your tow vehicle to the trailer without issue. This will give you a fully functioning 7 way connection on your trailer and keep you from having to worry about dealing with 2 trailer connectors.

I've linked one of our help articles on wiring a 7 way connector that you may want to reference during the installation process, as well as a wiring diagram that you can refer back to when wiring your junction box. I do recommend testing the wires on your existing 4 way connector to make sure that everything is wired correctly, since wire color isn't always consistent.

expert reply by: Erik B