How Do Electric Brakes on Pop-Up Campers Work?by Don Bowman
Electric brakes use electromagnets in place of wheel cylinders to actuate the brakes. A form of braking power, be it surge or electric, must be used on any towed vehicle that weighs over 1,000 pounds (such as a larger pop-up campers). On vehicles with dual axles that weigh over 5,000 pounds, brakes are needed on both axles. Electric brake pressure is controllable in both forward and reverse where surge brakes need something to release the brake fluid pressure when in reverse or the brakes would stay on.
Electric trailer brakes get pressure by varying the amount of voltage to the electromagnets. This is accomplished by a controller that is mounted on the bottom left of the dash. The controller is hooked up to the brake pedal arm--usually with a rod. There is a handle control and an adjustment for voltage on the front of the controller. When the brake pedal is depressed, a voltage from 1 to 13 volts, depending on the amount of brake pressure being applied, is sent to the electromagnets in the brake drum. The electromagnets pull on a rod actuating the brakes. The more voltage sent, the harder the brakes are applied.
All towed vehicles must have some way of stopping the vehicle should it break away from the hitch. Small, lightweight vehicles rely on the safety chain. A pop-up camper must use an auxiliary battery mounted on the tongue of the trailer behind the point of breakaway. Usually a cable is used to activate a solenoid that immediately applies full voltage to the brakes. The auxiliary battery and the brakes should always be tested before towing. To test the trailer brakes alone start the vehicle moving and without touching the towing vehicle's brakes use the hand controller and apply just the trailer brakes and see if it slows the tow vehicle down.