Service Trailer Brake System: How to Reset It Step-by-Step!

Learning to reset the service trailer brake system, which is the vehicle component entirely responsible for the behavior and performance of the trailer braking, is practical know-how for any driver.

Service Trailer Brake System

This will be especially true if the present situation makes it look like there might be something wrong with the system, and, in that case, you might need to know what you can do to make it work again. Use this article as your guide!

How To Reset Service Trailer Brake System Easily?

To reset the service trailer brake system easily, turn your vehicle on but don’t start the engine, press and hold the brake pedal for 15 seconds, then release the pedal and turn off the car. Wait a couple of seconds before turning it back on and checking if the warning message has cleared.

1. Turning off the Vehicle

One of the most crucial steps before commencing work is to turn off your vehicle and remove the key from the ignition. Doing so eliminates the risk of any accidental starting of the engine or electrical systems while you’re working on the brake system.

Turning Off Car Vehicle

Many people need to pay extra attention to the importance of turning off the vehicle before working on the brake system, assuming that it’s not necessary. However, this can be a costly and dangerous mistake. Imagine working on the brake system with the engine still running. Your fingers are accidentally caught in the moving parts. The results could be disastrous, causing severe injury or even death.

Furthermore, leaving the key in the ignition can also lead to unintentional brake system activation. If the brakes were accidentally applied, and you were unaware of it, it could cause damage to the system or even the trailer. It could even result in a road accident, putting you and all the other road users at risk.

2. Disconnecting the System

The brake controller is responsible for regulating the trailer’s brakes, which is essential when you must come to a sudden stop or even just slow down while towing a heavy load. Most trailer brake controllers are installed beneath the dashboard or on the vehicle’s center console, making them easily accessible for the driver. However, it’s vital to ensure that the controller is installed correctly and in a location that is convenient for the driver to operate.


Once you have located the brake controller, it’s crucial to disconnect it from the trailer before attempting to reset the system. This step is essential because if the trailer is still connected to the controller, it can continue to send signals to the system, which can interfere with the resetting process.

You can reset the system without any external interference by disconnecting the brake controller from the trailer. This makes diagnosing any issues easier and ensures the system is reset correctly. Additionally, it’s worth noting that disconnecting the brake controller from the trailer can also prevent any damage to the trailer’s braking system during the resetting process.

3. Turning on the Vehicle

Before attempting to reset the system, it is crucial to ensure that the trailer brake controller is disconnected from the trailer, as mentioned earlier. After disconnecting the controller from the trailer, the first step in resetting the service trailer brake system is to turn on your vehicle without starting the engine.

This step is important as it allows the electrical systems in your car to power up and communicate with the brake controller. It is crucial to note that some vehicles may require you to turn on the headlights, so consult your vehicle’s manual for specific instructions.

4. Holding the Brake Pedal Down

After turning on your vehicle, without starting the engine and waiting for the electrical systems to power up, the next step to reset the service trailer brake system is to press and hold the brake pedal for 15 seconds. Holding the brake pedal for 15 seconds is crucial to activate the system’s reset function.

Holding Car Brake Pedal Down

During this process, the brake controller will reset its internal memory, which can be essential in diagnosing any issues that may have occurred. It is also worth noting that this reset function varies by make and model, and it is crucial to consult your vehicle’s owner manual for specific instructions.

5. Releasing the Brake Pedal

After 15 seconds, release the brake pedal and turn off the vehicle. Once you have done so, waiting a few seconds before turning off the car is crucial. This short delay ensures the system has ample time to complete the reset process. During this time, the brake controller communicates with the vehicle’s electrical system, ensuring that all the data is accurately transmitted and the system is reset correctly.

It is also vital to note that turning off the vehicle after releasing the brake pedal will help save battery power. This break in the process allows the vehicle’s electrical system to shut down and conserve energy.

6. Checking the Dashboard

When checking the dashboard for the warning message, you should pay close attention to any additional notices or indicators that may appear. For instance, some vehicles may display an error code or an icon indicating an issue with the trailer brake system.

Checking Car Dashboard

When reconnecting the brake controller, it is crucial to make sure the connection is secure and tight. Loose connections can cause erratic behavior in the trailer brakes, leading to unsafe towing conditions. Before hitting the road, it is a great practice to test the trailer brake system to ensure it functions correctly.

It is worth noting that some modern vehicles come equipped with a built-in brake controller that integrates with the vehicle’s anti-lock braking system (ABS). In such cases, the reset process may differ from a standalone controller.

7. Testing the System

To begin testing, connect your brake controller to the trailer, ensuring the connection is secure. Verifying that the trailer is connected correctly to the controller is essential, as any loose or disconnected links can lead to system malfunctions or even accidents.

Once the connection is secure, take your vehicle for a short test drive, preferably in a quiet area with minimal traffic. This test drive will allow you to test your brakes in a controlled environment before hitting the road.

To test the brakes, apply the brake pedal and ensure they function correctly. If your brakes work correctly, you should feel the trailer’s brakes activate and help slow down the vehicle. Testing the brakes at various speeds and intensities is essential to ensure they function correctly in different driving scenarios.

During the test drive, also pay attention to any warning lights or messages that may appear on your dashboard. These could indicate a problem with your trailer brake system and should not be ignored. Suppose you do encounter any warning messages or lights. In that case, you should consult your vehicle manual or a professional mechanic to address the issue before continuing with your journey.

8. Proper Maintenance

When it comes to maintaining the service trailer brake system, you first need to check for frayed wires. Over time, the cables connecting the brake controller to the braking system can become frayed or damaged, affecting the system’s ability to function correctly. If you notice any frayed wires, they should be replaced immediately.

Proper Maintenance of Car

Next, check the connectors for any signs of damage or wear. The connectors are the small metal pieces that connect the wires to the controller and braking system. If damaged or worn, they may be unable to provide a reliable connection, leading to issues with the braking system.

Finally, check the brake pads for any signs of wear. The brake pads are the small pads that press against the trailer’s brake drums to slow it down. Over time, these pads can become worn and need to be replaced. If you notice that the brake pads are worn, they should be replaced asap to ensure the system can function correctly.

9. Monitoring It Regularly

You should inspect before and after every trip to ensure everything works well. An inspection before your trip allows you to identify and fix any issues before hitting the road. At the same time, an assessment after your trip helps you identify any wear or damage that may have occurred during the journey.

During the inspection, you should check the brake controller, lines, and pads for any visible signs of wear and tear. The brake controller is responsible for communicating with the trailer’s braking system, so it is essential to ensure it functions correctly. The brake lines should be free of leaks, cracks, or kinks, and the brake pads should not be worn out or damaged.

Apart from visual inspection, you should also test the system to ensure it works correctly. This can be done by connecting the trailer to the vehicle and applying the brakes to see if the trailer brakes respond accordingly. You should also test the emergency breakaway system, designed to use the trailer’s brakes in case it becomes disconnected from the tow vehicle.

It is essential to note that the type of brake system installed on your trailer may vary depending on the the trailer. Some trailers may have electric brakes, while others may have hydraulic brakes. Knowing the type of brake system installed on your trailer is crucial, and how to maintain it properly is vital.

10. Getting Professional Assistance

If you notice any issues with the system, such as the brakes not responding or the warning message appearing again, take your vehicle to a professional mechanic to have it checked. Attempting to fix the trailer brake system alone, especially if you are not experienced, can be dangerous and lead to further complications. A professional will have the necessary supply of tools and knowledge to properly diagnose and repair any issues with your brake system.

Additionally, having your brake system inspected at least once a year or before any long trips it is recommended that you ensure that it is in good working condition. This can prevent potential safety hazards while towing and give you peace of mind during your travels.


Resetting the service trailer brake system is a simple process you can do yourself with some knowledge and some essential tools, as you will have gathered from the information in the article above. If you want some final revision,

it’d be a good idea to check the following points:

  • To reset the service trailer brake system, turn off the vehicle and remove the key from the ignition.
  • Disconnect the brake controller from the trailer to avoid interference with the resetting process.
  • Turn on the vehicle without starting the engine, and press and hold the brake pedal for 15 seconds to activate the reset function.
  • Release the brake pedal and turn off the vehicle, then wait a few seconds before turning it back on to ensure the system has reset correctly.
  • Check the dashboard for warning messages and test the brake system before hitting the road.

It would be ideal to make it a habit to perform routine checks on your trailer brake system, especially before embarking on a long journey. By taking these steps, you can rest assured that you are doing everything possible to prevent accidents and keep the system in top condition at all times!


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