A proportional or inertia-based brake controller uses an electrical circuit called an accelerometer to sense changes in momentum. When the driver presses the brake pedal, the brake controller applies power to the trailer brakes in proportion to the vehicle's momentum.

What triggers trailer brakes?

Consisting of a battery mounted on the trailer and a cable connecting the trailer to the vehicle, the breakaway system is activated if the trailer breaks free, pulling the cable out of its plug with it. A switch will then trigger the battery and apply the trailer brakes to slow the trailer down.

How do trailer brakes work on a trailer?

The brakes are applied by using the trailer's own weight to slow the movement. When you step on the vehicle's brakes to slow down, with this type of non-electrical trailer brake system, a hydraulic cylinder is compressed and pressure is transferred to the trailer brakes which slows down the trailer.