How To Tell If Your Trailer Has Electric Brakes. The electric brakes are controlled by one of two methods. Notice the two green brake wires one end it tucked inside the back plate in this picture.

Each of your new brakes will have two wires for the brake magnet. You can control actuating the electromagnetic drums of the brakes through the controller it uses the electric energy from the towing vehicle and then helps stopping the trailer. But if your vehicle needs a higher stopping distance then you need electric brakes on your trailer.
You can control actuating the electromagnetic drums of the brakes through the controller it uses the electric energy from the towing vehicle and then helps stopping the trailer.
Either a surge device that is mounted on the trailer itself or a remote brake controller in the tow vehicle. On brake magnets these is no positive or negative they are not grounded so it does not matter which wire you connect. Any trailer that when stopping you can feel the trailer pushing the tow vehicle is a candidate for an electric over hydraulic brake system. Like ScottG said your truck is wired already.

