Trailer brake controls regulate the electric brakes on towed trailers, functioning independently of the tow vehicle’s hydraulic system. Typically installed under the dashboard, these units receive input from the driver via a manual lever or integrated control module. Proportional controllers apply braking force to the trailer based on the tow vehicle’s deceleration, utilizing a PWM signal to vary current to the trailer’s electromagnets. Timed controllers activate the trailer brakes based on pre-set intervals. Modern systems frequently include diagnostic features and compatibility with brake gain adjustment for customized performance.