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When towing a trailer, the importance of a good and efficient braking system cannot be overstated. The added weight and length of a trailer can make it challenging to handle and control your vehicle. One component that’s crucial to your ride’s safety while towing a trailer is a trailer brake controller. This device acts like a secret weapon in managing your trailer brakes.

What Is a Trailer Brake Controller?

A trailer brake controller (TBC) lets you control braking power so you can slow down as needed despite the trailer’s extra weight. It usually comes with a brake controller monitor that helps you monitor your trailer brake controller’s activity.

A TBC gets its electricity from the vehicle and applies a specific amount of braking power to your trailer brakes. It utilizes electrical circuits and trailer gain settings to regulate braking power.

Some controllers are designed to respond to the vehicle’s momentum, while others apply power depending on the driver’s input.

What Is a Brake Controller Monitor?

A brake control monitor lets you track the voltage delivery from the brake controller to the trailer. It helps you know if there’s any electrical fault that could put you, your passengers, and your cargo in danger. This monitor is usually under the instrument panel.

Brake control monitors have digital display screens that show the amount of pressure and braking power being applied to your brakes. Some can provide more specific data and conduct continuous diagnostics.

Types of Trailer Brake Controllers

Brake controllers fall under two types: proportional brake controllers and time-delayed brake controllers. Let’s look at each type in detail:

Proportional Brake Controllers 

A proportional brake controller applies the same amount of braking power to your ride and trailer. For example, if your vehicle is stopping slowly, the controller will ensure the trailer does the same.

Because it guarantees that the trailer and vehicle brakes get the same amount of braking power, this type of controller helps reduce wear on both brakes. It also helps achieve smooth braking.

How does it work? A proportional brake controller uses a motion-sensing device to monitor how fast your vehicle is slowing down. It relies on a pendulum-style circuit that makes it possible to apply a proportional amount of voltage to the trailer brakes.

When your ride is on a level surface, the pendulum usually points to the ground. It won’t send signals to activate the trailer brakes because it won’t sense any motion.

Once you start driving, the pendulum usually points toward the vehicle’s rear due to the motion. Stepping on the brakes would make the pendulum swing forward.

The amount of braking power the controller will send to the trailer brake depends on how far the pendulum swings.

Time-Delayed Brake Controllers

With a time-delayed brake controller, you can manually set the amount of brake power to send to your trailer brakes depending on the trailer’s weight.

 Because this controller needs a lot of human intervention, there will always be a delay when you press your brakes. But don’t worry; it’s equipped with a sync switch that lets you adjust the length of the delay.

Time-delayed brake controllers are easier to install and more affordable than proportional brake controllers.

What Does a Brake Controller Installation Entail?

Installing a brake controller isn’t rocket science. While the steps could vary depending on the vehicle and the process usually involves the following:

  • Disconnecting the car battery
  • Mounting the brake controller in an easy-access area
  • Plugging the unit using a vehicle harness

On some vehicles, the wirings must be spliced to connect the controller.

If you’re not comfortable doing the installation by yourself, you can always ask a professional to do it for you.

Where Is the Best Place to Mount a Brake Controller?

You can install a brake controller in any area that you can easily access. Most drivers choose to install their brake controller under the dashboard, usually in an area that’s directly above their right leg.

Calibrating a Trailer Brake Controller

Most brake controllers are self-calibrating. However, if yours needs calibrations, make sure your vehicle is parked on a flat surface before you plug the trailer brake controller into your tow vehicle.

Adjusting Your Trailer Brake Controller’s Settings

After calibration, you might need to adjust the controller’s settings according to your vehicle, trailer, and the size of your cargo.

Change the trailer gain level and sensitivity setting based on the manufacturer’s recommendation. Then, test it to determine if it still needs further adjustments.

What Does Trailer Gain Level Indicate?

The trailer gain level refers to the amount of braking power that the controller will apply to your trailer brakes. It should always be based on the size of the trailer and the weight of your cargo.

For example, it’s recommended to set the trailer gain level to high if your trailer is huge. Likewise, it’s best to set the gain level to low if you’re towing a small trailer. This will help avoid brake lockup.

A lockup happens when the braking force exerted by your brakes exceeds the traction between the tire and the road surface, which can cause the wheels to skid or slide. Adjusting the gain level correctly helps ensure that the right amount of braking force is applied, promoting a safer and more stable braking performance.

Keep Your Towing Trips Safe

Hauling a heavy trailer can be dangerous. Aside from installing a brake controller, it also helps to make a trailer safety checklist that you can consult before any trip. It could include essential tasks like checking your tires and the condition of your ride’s suspension before the day of your trip or delivery.

To help you get started, here’s the trailer safety checklist followed by the National Wildfire Coordinating Group in assessing trailers that transport fuel.

About The Author
CarParts Research Team
Written By Research Team

Automotive and Tech Writers

The Research Team is composed of experienced automotive and tech writers working with (ASE)-certified automobile technicians and automotive journalists to bring up-to-date, helpful information to car owners in the US. Guided by's thorough editorial process, our team strives to produce guides and resources DIYers and casual car owners can trust.

Any information provided on this Website is for informational purposes only and is not intended to replace consultation with a professional mechanic. The accuracy and timeliness of the information may change from the time of publication.

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