Brake Controller Troubleshooting (Here Is What To Do)

brake controller troubleshooting

Trailer brake controllers are an essential component of towing vehicles, allowing for safe and controlled braking of trailers.

However, like any other electronic device, brake controllers can experience issues that need to be addressed promptly to ensure safe towing experiences.

In this comprehensive guide, we will explore the common problems that can arise with trailer brake controllers and provide step-by-step instructions on how to troubleshoot and inspect them effectively.

1. Understanding the Functionality of Brake Controllers

Before delving into the troubleshooting process, it’s essential to understand how brake controllers work. Brake controllers serve as the interface between the towing vehicle and the trailer’s braking system.

When the driver applies the brakes in the towing vehicle, the brake controller receives a signal and sends an appropriate amount of electrical current to the trailer’s brakes.

This current controls the intensity of the braking action, allowing for synchronized and proportional braking between the towing vehicle and the trailer.

2. Common Problems with Brake Controllers

Brake controllers can encounter several common issues that need to be addressed promptly to ensure their proper functioning. Let’s explore these problems and how they can impact your towing experience.

Incorrect Installation

One of the most common issues with brake controllers is incorrect installation. It is crucial to follow the specific installation instructions provided by the manufacturer to ensure optimal performance.

Improper leveling or mounting of the brake controller can lead to inaccurate sensing of the vehicle’s movements, affecting the proportional braking action.


Brake controllers may sometimes appear unresponsive, failing to activate the trailer’s brakes when the towing vehicle’s brakes are applied.

This can be caused by various factors, such as blown fuses, loose wiring connections, or a faulty brake controller. Addressing these issues is essential to ensure the effective braking of your trailer.

Inadequate Braking Intensity

Another problem that can occur with brake controllers is inadequate braking intensity. This can manifest in two ways: excessive braking force or insufficient braking force. Excessive braking can strain the trailer’s brakes and potentially lead to wear and damage.

On the other hand, insufficient braking force can put additional strain on the towing vehicle’s brakes, potentially leading to premature wear and reduced stopping power.

Wiring Issues

Wiring problems, such as frayed wires, loose connections, or improper connections, can also affect the functionality of brake controllers.

These issues can cause a range of symptoms, from unresponsive controllers to unpredictable braking patterns.

Checking the wiring and addressing any issues is vital for maintaining proper brake controller performance.

Electronic Interference and Compatibility Problems

Modern vehicles are equipped with various electronic systems that can interfere with brake controllers. Certain systems, such as anti-lock brake systems or adaptive cruise control, can cause compatibility issues, affecting the communication between the towing vehicle and the trailer’s brakes.

Resolving these compatibility problems may require professional assistance or the use of electronic filters.

Faulty Displays or Signals

Brake controllers with digital or LED displays may exhibit display errors or faulty signals. Error codes or indicators that do not function correctly can be indicative of internal controller issues or problems with the trailer connection.

Understanding the meaning of these codes and following the manufacturer’s troubleshooting steps can help resolve these problems.

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3. Step-by-Step Troubleshooting Process

Now that we have identified the common problems with brake controllers, let’s explore a step-by-step troubleshooting process to effectively address these issues.

Step 1: Connect the Trailer and Locate the Brake Controller

To begin troubleshooting, connect your trailer to the towing vehicle, ensuring a secure connection. Sit inside the vehicle where the brake controller is easily visible and accessible.

Keep the brake controller’s owner’s manual nearby as a reference guide throughout the troubleshooting process.

Step 2: Check the Mounting and Positioning of the Brake Controller

Inspect the position of the brake controller to ensure it is mounted correctly. Proportional brake controllers require specific leveling and positioning to accurately sense the vehicle’s movements.

Consult the owner’s manual for your specific brake controller to determine the recommended mounting angle and adjust the unit if necessary.

Step 3: Examine the Display for Troubleshooting Codes

If your brake controller has a digital or LED display, check for any troubleshooting codes displayed on the front panel. These codes can provide valuable insights into the specific problem affecting your brake controller.

Reference the owner’s manual for a complete list of troubleshooting codes and follow the recommended adjustments or actions accordingly.

Step 4: Verify the Wiring Connection to the Battery

If the brake controller shows signs of no power source, check the wiring connection at the positive and negative battery terminals of the towing vehicle.

Ensure that the positive terminal is securely connected to the black power wire coming from the brake controller, while the white wire is properly grounded to the negative battery terminal.

Step 5: Test the Voltage Continuity between the Controller and Trailer Connector

With a 12-volt test light, check the continuity of voltage between the brake controller and the trailer connector harness.

Begin by holding the test light to the trailer connector wire port at the back of the brake controller, confirming the presence of 12-volts of power. Then, hold the test light to the wire connection port on the trailer connector at the rear of the vehicle.

If there is a noticeable decrease in power at the trailer connector compared to the brake controller, there may be wiring issues that need to be addressed.

4. Preventative Measures and Maintenance Tips

In addition to troubleshooting brake controller issues, it is important to implement preventative measures and perform regular maintenance to ensure their longevity and optimal performance. Here are some tips to keep in mind:

  • Follow the manufacturer’s installation instructions precisely to ensure proper mounting and positioning of the brake controller.
  • Use high-quality and appropriate gauge wiring for the installation to handle the maximum current that may be drawn during braking.
  • Regularly inspect the wiring connections for any signs of damage, such as frayed wires or loose connections. Address any issues promptly to maintain proper functionality.
  • Clean the brake controller’s display and the trailer connector regularly to prevent dirt or corrosion that may interfere with the signals.
  • Periodically test the brake controller’s functionality by towing the trailer in a safe environment and conducting controlled braking tests.
  • Keep the brake controller owner’s manual and contact information for technical support readily available for quick reference and assistance.

By implementing these preventative measures and performing regular maintenance, you can minimize the likelihood of brake controller issues and ensure safe and reliable towing experiences.


Trailer brake controllers play a vital role in ensuring safe and controlled braking while towing. Understanding the common problems that can occur with brake controllers and knowing how to troubleshoot and inspect them effectively is essential for safe towing experiences.

By following the step-by-step troubleshooting process outlined in this guide and implementing preventative measures and maintenance tips, you can maintain the functionality and reliability of your brake controller.

Remember, if you encounter any complex issues or require further assistance, it is always advisable to consult a professional with expertise in trailer brake controller solutions. Happy and safe towing!

Steve P.

Steve is an automotive technician, technical writer, and Managing Editor. He has held a lifelong passion for cars, with a particular interest in cars like the Buick Riviera. Steve is based in Boise, Idaho.

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