How Do Electric Trailer Brakes Work?

When you are on an adventurous journey on a trailer, you don’t care about stopping. But sometimes you may want to slow it down or stop at some point. 

That’s when you will need a trailer’s braking system. But having an electric braking system is not enough. Knowing how do electric trailer brakes work is also important.

Learning about an electric trailer brake is essential before hitching up your trailer. Can we have your undivided attention? Because we are going to discuss everything that you should know about electric trailer brakes.

What is an electric trailer brake?

An electric trailer brake is a braking system that requires electricity to operate. It’s also known as an
electric friction brake. Electric power from your travel trailer activates the brake drums. The brake controller organizes the motion of your vehicle. 

Stepping on the pedal activates the system through the electric trailer brakes wiring.

This system utilizes electrical power to control the speed of your vehicle. This system ensures your safety by putting pressure on the brakes whenever needed.

How do electric trailer brakes work?

Here are the major
trailer electric brake kits that make this thing work:

  • Shoe hold-down spring
  • Primary and secondary shoes
  • Reactor and adjuster spring
  • Magnet and adjuster
  • Actuating arm

By pressing the brakes you create a current signal between brake control and the trailer brakes. As a result, an electrical connection happens between the trailer and the braking system. There is an electrical connection among the trailer connector, axle brake, and trailer lights.

The electric trailer brake magnet has 2 conductor wires connected to the trailer wiring. Electricity makes the magnet allured to the drum face by magnetizing it. This contact causes the brake magnet to rotate. This makes the actuating arm move.

The actuating arm causes friction between the shoes and the drum. The friction creates heat and the special ingredient of the shoes resist it. When the inner part of the drum gets pressed against the shoes, the wheels stop spinning.

How to install electric trailer brakes?

Be sure to remember these steps before installing the brakes.

  • Unplug the negative battery cable to prevent damage to you and the braking system.
  • Search for an appropriate location to place the controller. We recommend putting it to the side of your steering wheel.
  • Carefully drill holes for fixing the controller in its place.
  • Install and tighten the trailer electric brakes controller.
  • Connect the brake controller using a harness.

How to wire electric trailer brakes?

Let us tell you how to wire your electric trailer brakes into your vehicle. You can also check the
electric trailer brakes diagram given in the user manual.

Unplug the negative battery cable

Unplugging the battery ensures your safety while wiring. It also prevents damages to the parts of your vehicle.

Find the wiring of the brake controller

Every car has a factory connector or blunt-cut wiring for connecting a brake controller. You will find this wiring under the dash. Handle these wires carefully.

Set up the wiring connections

Strip and separate side wires. Then use a harness to splice them.

Remember these:

  1. Red means 12+ volt
  2. Blue indicates braked output to the trailer
  3. White means ground
  4. Blue striped white means stop lights

Connect color-coded wires at one place

Use a harness to splice the wires. Combine the butt connectors. Splice the wires by matching the colors.

  1. Connect blue brake and vehicle wires.
  2. Splice red wire to black brake wire.
  3. Combine white vehicle and brake wire.
  4. Combine the blue stripe white vehicle wire with the red brake wire.

Plug in the harness and supply power

It’s time to plug the harness into the brake controller. Then all you have to do is provide a power supply to the controller using a wire.

How to test electric trailer brakes?

You need to check your trailer’s drum brakes sometime. To do that you will need a battery with a +12V power supply. You can use this method to test 7,10, and
12-inch electric trailer brakes.

Connect the power supply to the trailer’s plug or the wires. If your drum brakes are in a good condition, you will hear a soft humming sound.

How to adjust trailer brakes

For your safety, you should check
electric trailer brakes adjustment every 3 months. For safe towing, adjusting trailer brakes is a must. How to adjust? Here’s the process:

  • Carefully jack up your vehicle
  • Withdraw the brake cover
  • Fasten the adjustment wheel
  • Check if something is preventing tires from spinning freely
  • Place the cover in its place and tighten the nuts

Electric trailer brakes troubleshooting 

Electric trailer brakes malfunction like other machines. Sometimes you may notice that your
electric trailer brakes are not working. You may even notice a supply of power to the trailer brakes but they are not working.

Problems related to brakes happen mostly because of wiring.

  • Check the brake controller, power supply to controller, power supply to the brake pedal, and adjustment knobs.
  • Check the power supply to the trailer connector. If you don’t find any problem, check the brake controller.
  • If there’s a power supply between the trailer connector and the tow car, check the ground of the trailer. If the brake doesn’t work, check the connection between the magnet and the wires.
  • In case the brakes don’t release or make a noise, check the brake switch. Remove the wheels and check the magnet.


  • How to tell if electric trailer brakes are working or not?

Search for a slide bar on the controller. It should contain an indicator light. Slowly move ahead with your vehicle and pull on the slide bar. If you feel any resistance, your brakes are in good condition.

  • Do electric trailer brakes adjust themselves?

Yes, they can and they do. But the electric trailer brakes need to be adjusted initially for self-adjusting.

  • How are trailer brakes activated?

The breakaway system consists of the trailer, battery, and a connecting cable. When a trailer pulls out the plug by breaking free, the battery will activate the brakes.

  • Are electric trailer brakes directional?

Yes, they are directional. So you should fit your trailer with appropriate right and left side brakes.

  • Are electric trailer brakes any good?

These brakes will give you good control and ease. If you adjust your electric trailer brakes well, they will work perfectly. 

  • How do you break in electric trailer brakes?

Get your car to run at 40 mph. With the help of the brake controller, you can increase the electrical power of the trailer brakes. The speed of your trailer will move back to 20-25 mph if you put in 8-10 volts. Now get your hands off the brake controller and repeat this process about 20-50 times.

  • How to use a trailer brake controller?

Look for the controls of the braking force. Either you will notice these controls in the digital display or you will see some buttons to control. The normal amount of braking force that appears on the controller is 0-10. A higher number means higher braking power.


Hopefully, now you know
how do electric trailer brakes work. Be sure to always check your brakes and other instruments before going for a ride. Come back for more information on this topic.

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