How to Wire Trailer Brakes

There are a lot of factors that are linked to wiring a trailer or an RV. While the manufacturers want to stick to a standard, there are still the unconventional ones who choose to be different. The purpose of this post is to give you the most common situation on how to wire trailer brakes. So for the majority of what is written here, you will be able to grasp the information provided here and determine the best way to wire trailer brakes alone. Although, today’s vehicles are refined to the point that putting a few extra lights can lead to fuses blowing up, wires melting, and maybe even lead to overall failure. To keep anything bad from happening, here’s the proper way to wire trailer brakes.


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Start with the trailer lights

Nowadays, there is no reason ever to strip, cut, or harm the original wiring that’s been placed on the majority of the trailers.

There are plug and play harnesses available in the aftermarket that lets you just plug the connector at the assembly tail light of the car and plug in the new one between the taillight and the original wiring of the harness. It is essential to buy the specific wiring kit for your car because the wrong one can cause damage to your trailer.

Wiring the trailer brakes


This part can get a little tricky, but the best idea is to pick a vehicle that is fresh from the factory with a trailer towing package. There are vehicles that already come equipped, like a 7-pin trailer light connector. Of course, the brake controller is not loaded yet, but the wiring that comes from the brake switch to the trailer plug is already there. Hooking the brake controller is easy if it’s the standard wiring that is being used which comes with the controller.

If you have a vehicle that requires you to start from scratch, this is what you need to do:

It can be easy to install and no special tools or drills are required. The brake controller only needs one small alteration so that the additional load from the car’s electrical system can be put aside. All of the connections should be made through the battery, but the wire that goes through the car’s brake switch needs to be handled differently. Instead of hooking it to the brake switch, you need to run that red wire to a dash push button switch that’s been mounted and go on from the switch back to the +Pos battery connection located at the inline fuse.

This is going to keep you from causing damage to the car’s original wiring. Keep in mind that the trailer brakes will only function when the new dash-mounted button is pushed. The trailer brakes will not work if you push down the brake pedal of the vehicle.

Several brake connector quick plug styles are made for different vehicles



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If there is no quick plug loaded on the trailer, you would need to tweak the light wiring of the brake. Search for the light switch of the brake – it can be mechanical or linked to the pedal and can sometimes be hydraulic that was placed inside the engine bay. No matter where it is placed, you would have to run a 12-volt power wire, ground wire, and a brake light wire going to the controller, and lastly, a wire that comes from the controller and back to the wiring connector of the trailer.

The placing wire on a brake controller can sometimes be too complicated for a beginner, but if you have enough skills, it is possible. Although, it is much better to consult a professional.

If you are one of the lucky ones to find that the brake controller already came with your trailer installed on the dash provided by the manufacturer, you should have no problem making the controller work with every standard electrical trailer brakes.

How does electricity make trailer brakes work?

The magnet found in the backing plate is composed of 2 conductor wires which tap straight into the wiring. When electricity is turned on, it magnetizes the brake magnet. The magnet has been attached to the drum face. When it touches this area, the friction causes rotation that moves the actuating arm and pushes the shoes against the drum. The special brake pads under the shoes resist the heat that is being caused by the friction. When the shoes start to press against the inner part of the drum, they stop the hub, and also the wheel that is touching the ground.

Find out which brake to use

An electrical connection on the trailer plugs inside the connector onto the vehicle. There are electrical wires that run from the trailer connector and back to each brake on the axle, and also to the trailer lights in order to make a complete circuit. When the driver uses the brakes, it sends a current to the vehicle’s brake control. The brake control will then send the current back to the trailer in order to activate the brakes.

Now that you have read the proper ways on how to wire trailer brakes, you can assess yourself if you can do it on your own or if you are going to seek a professional to do it for you. This post also aims to make you understand how trailer brakes work and determine which one to use. If you own a trailer and want to know more about trailer brakes and trailer brake controllers, there is a buying guide that you can refer to so you can read and choose which suits you best. There are a lot of trailer brake controllers being sold today, but the ones you will find in the given buying guide are the best ones in their category.

Remember to follow the tips given properly to avoid any accidents or keep something from blowing up because you don’t want to ruin anything.

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