A brake controller supplies power from a vehicle to a trailer's electric brakes. There are two types of brake controllers; Time Delay Activated and Inertia Activated.

Even though each type of controller has a specific function and purpose, controllers all share the following properties:

They are wired the same way.

The driver can adjust how much braking power is applied.

Each type has a manual override switch that allows the driver to apply the electric trailer brakes.

Time Delay Brake Controllers

Time Delay controllers are also known as solid-state controllers. They are activated when the brake pedal in the tow vehicle is depressed. Once activated the controllers apply voltage to the trailer's brakes using a Time Delay Circuit.

Solid-state controllers are generally more inexpensive than Inertia Activated controllers. In addition, they can be mounted just about anywhere and do not take up a great deal of space. A fairly common issue with the time-activated controller is pulsing brakes when controls are set too aggressively. Gain problems can be rectified with a pulse preventer to isolate the controller from the vehicle's electrical system.

Inertia Activated controllers are also called Pendulum Style controllers. A pendulum controller senses the slowing movement of the vehicle and applies increased voltage to the brakes as the vehicle slows. A pendulum-style controller will slow the trailer at the same rate the vehicle slows down. When the Inertia activated control is properly adjusted, the trailer will decelerate at the same speed as the towing vehicle. A result of this is increased braking efficiency and reduced wear on the brakes.

The pendulum-style controllers tend to be larger than solid-state controllers and have to be mounted in a level position (although there are some exceptions). They are also usually more expensive.