Electric brake controllers are used to apply the brakes of a towed trailer. When you press the brake pedal in your vehicle, the signal goes to the trailer’s actuator or brake magnet. The braking force depends on power / voltage applied to the trailer’s electromagnets. Usually, brake controllers feature a 4-wire configuration that you can hook up to the wiring of your braking system.

These wires are:

• Trailer feed – supplies brake power to the connector of the trailer
• Battery power – supplies power to the controller itself
• Brake switch – transfers power from the pressed brake pedal
• Ground – connects the controller to a grounded (negative) source

Installation process

1. Installing a trailer brake controller is not difficult and won’t take much time. You’ll need the controller itself, 7-way installation kit (6-way ones are available too) and 4-pole trailer connector (in case you don’t have it already).
2. Find an appropriate place to mount a 7-way connector, usually it is mounted on the bottom of the rear bumper. Secure a mounting bracket into your bumper employing self-tapping screws and then secure the trailer connector into this bracket. Plug the connector’s 4-pole adapter into 4-pole trailer connector of your truck or SUV. Screw the white wire into the frame to ground a 7-way connector.
3. Make a cut in the duplex cable’s rubber sheath and separate two wires inside. Using a butt connector, attach the black wire to the black wire on your 7-way connector and do the same for the white wire and blue (brake) connector’s wire. Route the duplex wire under your vehicle up to the engine compartment avoiding hot and pinch-risky areas.
4. Select the suitable location for the mounting bracket inside your SUV or truck. The most common location is the right lower side of the dashboard, because it ensures easy access to the brake controller in extreme situations. Drill the needed holes and install the bracket into the dashboard using screws. Secure the brake controller into the bracket and connect the wires.
5. Separate the brake wire, which is now white, from the black 12V hot lead, route it via the vehicle’s firewall and connect to your brake controller. Connect the controller’s blue wire to the white duplex cable’s white wire using a butt connector. Mount circuit breakers in a safe location on the firewall or under the hood. Route a 12V hot lead to a 40-amp breaker through ring terminals and then to the battery’s positive post. Route the black wire that comes out of the controller to another breaker and then to the battery’s positive post. Route the controller’s white (ground) wire to the battery’s negative post. Use the excessive brake wire or 12V hot lead to complete the connection in case of need. Inside the vehicle, connect the red controller’s wire to the wire carrying the signal of an engaged brake pedal using a quick splice.
6. Zip tie any excess or loose wires under your vehicle outside and underneath the dashboard inside. Remember that the wires should not interfere with gas and brake pedals and have to be kept away from excessive heat areas.