Service Trailer Brake System - What It Means and How to Turn Off • Road Sumo (2024)

If you always use your truck to tow a trailer, you should take care of your trailer brake system. For your safety, it must work flawlessly. In this article, I’ll discuss the service trailer brake system – what it means and how to turn it off.

When you see the ‘service trailer brake system’ message on your dashboard, it means there is a problem with the electrical wiring of the system or module that prevents electricity from flowing from the truck to the trailer.

The easiest way to turn off the trailer brake is to unplug the brake controller. If you disconnect this brake controller, no electricity or power will go to the brakes. However, if you cannot unplug the brake controller because it is hardwired, you can cut the output wire of the brake anywhere between the trailer brakes and the brake controller.

Read on to learn more about the service trailer brake system and how you can turn it off.

Service Trailer Brake System – What It Means and How to Turn Off

When you see the ‘service trailer brake system’ message on your dashboard, it tells you there’s a problem with the electrical wiring of the trailer brake or module. This prevents the power supply or electricity from flowing from the truck to the trailer.

The easiest way is to unplug the brake controller to turn off the trailer brake system. Once you disconnect the brake controller, no electricity will go to the brakes.

However, if the brake controller is hardwired, you cannot unplug it. The only thing you can do is to cut the brake output wire anywhere between the trailer brakes and the brake controller.

You can also reset the trailer brakes instead of turning them off. You must remove the wheel and use a ‘star wheel’ adjuster or a screwdriver.

Use the adjuster to tighten the brakes until you can no longer turn the wheels. Then loosen the tightness of the brakes until you can freely rotate the wheels again.

Trailer Brake Overview

To properly understand the work required to solve this issue, you must know what a trailer brake is. The trailer brake (controller) system used by your car can be an Original Equipment Manufacturer (OEM) or an aftermarket module or device.

This gadget is designed to help you control the speed of the trailer, as well as to stop it. It is typically mounted on the vehicle’s dashboard at the driver’s side.

This system will function in accordance with the brakes of the tow vehicle. It’s a different problem if your dashboard says Service Trailer Brake System with no trailer on the back of your car.

It can also reduce the speed of stopping the trailer using a time-delayed frequency. Most trailer brake systems have adjustment controls such as plus or minus tweaking.

Some examples of trailer brake systems are those installed in big boat trailers, enclosed trailers, travel trailers, and horse trailers.

What Does Service Trailer Brake System Mean

Error Message That Warns the Driver of a Disengaged Trailer

What does Service Trailer Brake System mean? The ‘service trailer brake system’ seen on the dashboard is an error message warning the driver that the trailer is disengaged from the towing vehicle.

Trailer Braking System Unable to Receive Power from the Towing Vehicle

It means that the trailer braking system can no longer receive power from the towing vehicle, so the system can’t function anymore.

Causes

In other words, when you see this message on your dashboard, you are being warned of a problem with the trailer braking system. It could either be a disconnection in the wiring, or the module is not working. In either case, the power supply from the towing vehicle to the trailer is disrupted.

Symptoms

Several other symptoms will appear after receiving the error message if this happens. These symptoms will show up as you try to stop the trailer. Some of the symptoms can include:

• Sharp noise coming from the brakes
• Sudden unresponsiveness or mushy feeling when engaging the trailer brakes
• Sinking brake pedal

So, if you ever experience these symptoms, you need to reset the trailer brake as soon as possible. If you don’t, it may lead to a horrible accident or, at the very least, damage to your vehicle and the trailer.

Don’t drive your vehicle with a trailer at the back of this warning message on your dashboard.

How to Turn Off and Reset the Service Trailer Brake System

Knowing how to turn off the “Service Trailer Brake System” is not very difficult. The process involves just a few steps. But you need the necessary tools to be able to do it.

Tools

The tools you will need are the following:

• Flathead screwdriver
• Hammer
• A piece of hardwood or small rock

Steps

You will also need a helper to make your work easier. Here are the steps you need to follow to turn off or reset the service trailer brake system:

1. Locate the Adjustment Nut on the Trailer

You need to find where the adjustment nut on the trailer is located. In most vehicles, it is situated in the back of the trailer’s brakes. This nut is typically located close to the axle. Once you are sure it is the adjustment nut, proceed to step 2.

2. Use the Screwdriver to Loosen the Lock Nut

The adjustment nut has a lock nut that secures it on the trailer brake. Use the flathead screwdriver to loosen this lock nut. Loosening this lock nut will enable you to perform the next step quickly.

3. Turn the Adjustment Nut Clockwise

Once the locknut is loose, you can now free the adjustment nut. The next thing you need to do is to turn the adjustment nut clockwise. Continue doing so until it is snug against the backing plate of the component. Be sure not to tighten the nut too much, or there will be complications.

If you follow these three steps correctly, you will have reset the trailer brake system successfully. However, if this warning message still shows up on your dashboard, it could be a problem with the trailer brake system itself.

You need to have this system checked by a competent mechanic for repair or replacement.

How Often Should You Examine Service Trailer Brakes?

If you use a trailer, you are advised to have its brakes examined and serviced after every 12,000 miles of use or at least once a year. However, if you use the trailer frequently or for long trips, you must service it more often.

Keep tabs on how frequently you use your trailer. In addition, watch out for any signs that the brakes are already wearing out. Stay on top of its maintenance schedule. This is the only way you can be sure that the trailer brakes are in good working condition and are functioning well.

Again, what does Service Trailer Brake System mean? A Service Trailer Brake System means an issue with your trailer brake wiring or module, which hinders the electricity flow from the truck to the trailer. You might notice other symptoms aside from this error message.

Service Trailer Brake System on Various Truck Models

In general, the trailer brake systems of different truck brands have the same principle of operation. This means they work similarly, although installed on other truck brands.

You may be wondering about your truck’s specific trailer brake system. Here are some relevant details about the trailer brake system of three different truck brands:

1. Silverado

The trailer brake system in a 2014 Silverado is located in the trailer. This is so that the driver of the towing vehicles can regulate the operation of the trailer brake.

The Silverado Service Trailer Brake System is designed so that the towing vehicle can travel smoothly while it tows a heavy load on its rear side.

However, this trailer brake system is susceptible to wire deterioration, binding, seizure, and corrosion. These problems will trigger the ‘service trailer brake system’ warning message.

That’s why regular servicing of the trailer brake system is necessary. If this is not done or ignored, problems in the trailer’s braking system will make it unsafe to operate.

2. Ram 1500

When the ‘service trailer brake system’ message turns up on the dashboard of a Ram 1500, it warns the driver that there’s something wrong with the trailer braking system.

There are some instances when the lights themselves are causing the problem. They are just flashing without being caused by any mechanical problem.

If you need to reset the trailer brake system in a Dodge Ram 1500, you need to do this:

• Remove the wheel and adjust the nut that controls the snugness of the brake to the wheel.
• You must use the ‘star wheel’ adjuster or a flathead screwdriver.
• Turn the controlling nut clockwise until it is so tight that you can no longer turn the wheel.
• Then loosen the nut until you can turn the wheel quickly and freely again.

3. GMC Sierra

If the dashboard on your GMC Sierra suddenly shows the ‘service trailer brake system’ warning message, most likely, your trailer is experiencing a faulty ITBC.

This acronym stands for an integrated trailer brake controller. Your vehicle’s ITBC may be encountering a module or wiring problem.

When this warning light shows up, it usually means a malfunction prevents the power supply or electricity from reaching the system. The system is not functioning simply because the connection to its power source is disrupted.

In other words, the ITBC cannot function as it should because no power will make it run. You should have the system examined by a competent mechanic immediately before you can tow a trailer again.

Is It Safe to Drive with the Service Trailer Brake System?

Yes, you can certainly drive your vehicle even if the service trailer brake system warning message comes up on your dashboard – just as long as there is no trailer connected to the back of your vehicle.

You must not connect a trailer to the back of your vehicle until you have completely fixed the cause of the problem. There is a reason why the warning message showed up on your dashboard.

If you don’t fix this issue, you may be causing more damage to your car and the trailer, not to mention the accident.

So, while it is safe to drive your vehicle, you are not advised to do so until you have the problem fixed. Your car should be 100% secure at all times before driving it anywhere.

Frequently Asked Questions

The service trailer brake system is a crucial safety topic that might have sparked a lot of questions in your mind. If you go on reading, you may find your answers on the ones listed below:

What Does the ‘Service Trailer Brake System’ on My Dashboard Mean?

When you see the ‘service trailer brake system’ pop up on your dashboard, it warns that something is going wrong with your trailer brake system.

You need to stop using your trailer if you see this warning message. If you continue using the trailer, it may cause an accident or damage your vehicle and trailer.

Is It Still Safe to Drive the Vehicle with ‘Service Trailer Brake System’ Warning Light on?

Yes, you can still drive your vehicle with this warning light. But don’t use it to tow a trailer if you don’t want to meet an accident or cause damage to your car and the trailer.

Why Does Service Trailer Brake System Warning Message Show Up on My Dashboard?

You will get this warning message on your dashboard for several reasons. One of the reasons is the electrical wiring of the trailer brake system is disconnected from its power source. So, even if the TBS has no problem, it will not work if no electricity will make it run.

Another reason is if the TBS itself is malfunctioning. If this is the case, you need to have it checked by a competent mechanic for repair or replacement.

How Can You Turn Off the Trailer Brake?

The easiest way to turn off your vehicle’s trailer brake is simply unplugging the brake controller. Once the brake controller is unplugged, it can no longer receive power from the power source.

But this isn’t easy to do if your brake controller is hardwired. If that’s the case, you can cut the brake output wire between the trailer and the brake controller. This will cut off the power supply of the brake controller.

How Can I Reset the Service Trailer Brake System?

To reset this system, you must remove the wheel and adjust its adjustment nut using a ‘star wheel adjuster’ or a flathead screwdriver.

You need to tighten the brakes until you can’t turn the wheel anymore. After that, you need to loosen the nut to turn the wheel freely. If you successfully do this, you have reset the trailer brake system of your vehicle.

Does the Trailer Brake System Have a Fuse?

Yes, a trailer brake system uses a fuse as a safety device. If there is a malfunction in the system, the first component that will give way is the fuse so the entire system will not be compromised. Typically, the rating of the fuse is 30 amps. You will find this fuse inside the fuse box in the engine bay.

How Much Will It Cost to Fix the Service Trailer Brake System?

The typical cost to fix this issue is about $300. This amount will pay for the parts and labor. The system will be fully installed in your vehicle.

But this estimated cost can go up or down depending on the type of brake controller of your vehicle and the actual labor cost that the car service tech will charge you.

No matter how much the repair will cost, you must have your trailer brake system fixed for safety, mainly if you frequently use your vehicle to tow a trailer.

In Closing: The Meaning of Service Trailer Brake System and How to Turn It Off

If the ‘service trailer brake system’ message comes up on your dashboard, it signifies that the module or the system’s electrical wiring is experiencing a problem preventing the electricity from flowing from the truck to the trailer.

You need to turn off the trailer brake system. The easiest way to do this is to unplug the brake controller. Once the brake controller is disconnected, no power will flow to the brakes. But if the brake controller is hardwired, you can’t unplug it.

What you can do is cut the output wire of the brake. Cut it anywhere between the brake controller and the trailer brakes. This will effectively cut off the power supply of the brake controller.

Read next:

How Much Weight Should Be on the Tongue of a Trailer?