There are a many different warnings that can be noted throughout your vehicle dashboard to alert you of issues. One warning you may encounter is the Service Trailer Brake System message. What does it mean? How can you fix it?
In this article, I’m going to explain what this trailer brake warning is. I’m also going to provide a couple of suggestions that may help clear the warning.
What Does the Service Trailer Brake System Message Mean?
The Service Trailer Brake System message indicates a failure of the trailer brake system because of wiring or other failure. The trailer being towed could have an inadequate power source thus eliminating the ability for the brake to engage.
There may be more than just a warning. You may experience difficulty stopping the trailer due to the malfunction.
Strange noises may also occur when you brake. Without the right amount of power there would also be an issue with the lights and electronic equipment on the trailer.
What are Trailer Brakes?
The trailer brake controller can either be OEM or aftermarket depending on when installed. The device is mounted on the vehicle that is towing the trailer to give the driver better control over the stopping of the tow truck/trailer/vehicle instead of just relying on the brake pedal.
The controller is mounted to the dashboard (just to the left or right of the steering wheel) where it is easy to reach for the driver.
With this system, the brake engages proportionally to the vehicle’s brake (there may be a slight delay), and can usually be adjusted with the plus and minus buttons on the display.
Trailer brake systems can use a variety of fitments on the trailer. It is easy with a closed trailer, camper trailer, horse trailer, or boat trailer.
Causes of Service Trailer Brake System Message
If you receive a service trailer brake system message on your dashboard, the cause could be due to a blown fuse, a bad brake light switch or a bad trailer brake control switch. A trailer brake system message could also result from damaged wiring.
If you own a Chevrolet, Cadillac, or GMC vehicle, there is a technical service bulletin on the service trailer brake system message that you should consider before performing any repairs.
#1. Blown Fuse.
All real electronic systems running on your vehicle rely on a fuse to control and monitor power. If an excessive voltage with excessive current occurs, a fuse may blow.
In some cases, you can see how blown fuses can be tied to a bigger problem, and if you replace the fuse and it blows again, that problem is revealed quickly.
Looking in your car’s owner manual to find the right fuse and see if it is blown, if it is blown, replace it with an equal fuse and get back to driving.
#2. Bad Trailer Brake Control Switch.
Under your dashboard, you are likely to find a workable trailer brake controller switch in most car models with a trailer brake system.
This is often called a controller switch, and it can go bad, and you need to simply replace it. Alternatively, the connector could be dirty or contaminated.
If you own a Chevrolet vehicle and have the Service Trailer Brake System warning message, frequently the cause is a bad trailer brake controller switch located under your steering wheel.
Your first reaction should be to simply clean the electrical connectors, and then see if that solves the dashboard warning light. If not, you will need to replace the switch.
#3. Bad Brake Light Switch.
You could potentially see the warning light on your dashboard also when a brake light switch is bad. The good news replacing that part is not usually costly.
The brake light switch is also located on the brake pedal, most of the time it easy to self-replace that part. However, make sure that you finish with a proper switch adjustment.
#4. Bad Sensor/Master Brake Cylinder.
Brake systems have a master cylinder, and its connected the number of sensors that contribute toward a well-operating brake system. When anything starts to fail, it is possible for this message to light up.
In other cases, this message will come on as well as others indicating that their is a bigger brake system problem occurring. Depending on what sensor is failing you may be looking at a more expensive repair.
#5. Damaged/Faulty Wiring.
When wires are frayed or poorly damaged you cannot get the signals to go where they are applicable. This faulty wiring can lead to the brake system message on your dash.
If you are not adept at finding electrical faults, this may be a job better suited for a professional. Essentially every single connection or wire needs to be thoroughly vetted for damage before it is considered repaired.
Surge vs. Electric Trailer Brakes
Surge Trailer Brakes
The surge brake is hydraulic in nature and is the most basic setup that still provides for better safety on the road.
It uses the momentum of deceleration of your vehicle to brake your trailer. This process operates under the pressure theory, which says the more pressure applied to the system, the more braking occurs. This setup allows you to make hard stops without creating more wear on the brake parts.
So far, we see all benefits and favour the lower price and less effort required. However, surge brakes do have a loss of some control which is a downside.
Electric Trailer Brakes
The electric trailer brake is very adjustable. You can change the force based on how you drive and the braking force required.
With a controller, the braking functions are very easy to control and service is easy and infrequent. You have more control of this situation as compared to surge brakes.
Electric trailer brakes generally are more expensive. You also have to pay a greater cost out of pocket if you want to have the system professionally installed, which is significant to include in your costs and decision.
Could there be an issue with a trailer brake fuse?
Most trailer brakes operate with a 30-amp fuse, which, of course, could have blown. Beware, however, if this is the problem, the brakes won’t function at all because juice isn’t getting to the brakes.
To ascertain this as a potential issue, first, you need to locate the fuse. You can reference the fuse diagram located in the owner’s manual.
Next, you can use a multimeter to ensure the 30-amp fuse is receiving the proper power. If you do replace the fuse, be sure to always get the correct amperage or you could risk electrically damaging the system.
Average Cost to Repair the Trailer Brake System
Depending on the situation, you could spend anywhere from $0 and $500 repairing your trailer brake system.
If you only need an adjustment, you just lost a little bit of time and used your screwdriver. There are situations that will cost you more to repair, however.
As an example, if you need a new fuse, you may only spend $5-$15. Again, this is something you can most likely replace yourself. Once you find the fuse, it should take you only a matter of minutes.
Other than these two issues, you may need parts replaced in the trailer brake system or you may be looking at a complete replacement. Replacement costs will vary based on many factors.
For starters, you will spend more on OEM equipment than on aftermarket parts. You also need to factor in the make and model of your vehicle, as some are much more expensive to work with.
Finally, you need to factor in the location where you’re getting the work done, as mechanics in urban locations can often charge much more than rural service shops.
Is It Safe to Drive with Service Trailer Brake System Message?
No. There are many messages that can be handled at a later date with little concern. However, Service Trailer Brake System message is not one that should be treated so lightly, especially if you are towing a trailer.
This problem is going to cause issues when trying to brake while having a trailer attached to your vehicle. If you do not resolve the issue and just continue driving, it is possible that this experience will turn into a chain-reaction incident that could result in a serious accident.
How do you reset a Service Trailer Brake System Message?
How to reset service trailer brake system message can depend on what trailer brake system your vehicle has.
In most cases, it will disappear on its own if you fix the issue that caused the message to pop up anyway. Depending on the vehicle make model, you may also need an OBD2 scanner to reset the system.
How do you reprogram a trailer brake control module?
If you want to reprogram a trailer brake control module, you need the specific diagnostic device for trailer brake system that your vehicle uses. However, you can also manually adjust trailer brakes using the controller for many trailer brake systems.
How do you troubleshoot an electric trailer brake controller?
To troubleshoot your electric trailer brake controller, you may need the manufacturer’s specific diagnostic computer that works with your brake controller. However, in many situations you just need a multimeter and wiring diagram for the brake regulator.