How Do Electric Trailer Brakes Work?

Electric trailer brakes rely on an electrical connection to a brake control unit installed in the tow vehicle. The trailer receives a signal from the brake control unit when the tow vehicle’s brakes are applied. This signal activates the magnets in the trailer’s braking system which stops the trailer. Using electric trailer brakes allows you to safely slow and stop a trailer when it is loaded or unloaded.

Components

The trailer braking system consists of three principal components: an electric brake controller, an electrical plug connecting the vehicle and trailer and electric brake assemblies mounted on the trailer’s wheel assembly.

Electric Brake Controller

There are two types of brake controllers available to operate electric trailer brakes. 

• A proportional brake controller provides smooth and quick braking with minimal wear on the vehicle and trailer’s brakes. An electrical wire connects to the brake pedal switch and activates when the pendulum circuit senses a stop. The motion sensing device applies power to the trailer brakes in a manner that matches how fast the vehicle is stopping. With proper adjustment to the control unit, the trailer decelerates at an equal rate as the tow vehicle, allowing the most efficient trailer braking.


• A time-delayed brake controller allows the driver to adjust the amount of power sent to the trailer’s braking system based on the trailer weight. The delay of the signal can be shortened or lengthened using a manual sync switch. Time-delayed brake controllers send the same amount of braking power to the trailer with every stop. Inexperience or incorrect setup can cause uneven vehicle or trailer brake wear.

Electrical Plug

An electrical plug connects the electrical system from the tow vehicle to the trailer and provides a path for the signals to the electric brakes. When the brakes are applied, an electrical signal runs through the wiring into a plug at the back of the vehicle which connects to a plug on the front of the trailer. From the trailer plug, the signal runs through an electrical wire attached to the trailer’s electric brakes.

Electric Trailer Brakes

Electric trailer brakes attach to the wheel assembly on one or more axles of the trailer. The electrical current from the brake controller energizes the magnet located on the actuator arm and attracts it to the brake drum. With this attraction, the magnet tries to turn with the bake drum. The rotation of the trailer’s brake drum forces the brake shoes outward; slowing down the trailer.