Brake Lamp Bulb Fault (Meaning, Causes & Solutions)

One vital safety feature in your car is a functioning brake light. Whenever you press your brake pedals, your brake lights are meant to shine bright, warning drivers at the rear that your car is slowing down or halting.

This singular feature grants drivers at your rear enough opportunity to react by applying their brakes or swerving off your rear. This feature prevents collisions and accidents.

A Brake lamp bulb fault warning is displayed whenever your braking system is faulty in any way that will cause your vehicle’s brake lamps to malfunction in any strange way, like either flickering or not even receiving power.

These types of problems do not happen every day. Still, if you are experiencing a similar problem with your vehicle, after reading this article, you will have gained enough knowledge to solve the problem.

In addition, you will also be enlightened on what could have triggered the Brake Lamp Bulb Fault message, the cost to fix the problem, and more.

Let’s Begin!

Any issues in your braking system which result in your vehicle’s rear lights going out are called a “brake lamp bulb fault.”

A vehicle’s brake lights depend mainly on its electrical system, which runs via several fuses and switches to protect the electrical circuitry.

So If your brake lights aren’t working correctly, an essential system fuse might be blown, the bulbs at the brake light positions are faulty, or electrical connections (wiring) are damaged.

Also Read: Service Brake Assist (Meaning, Causes & Fixes)

Brake Lamp Bulb Fault: Causes and Solutions

Brake Lamp Bulb Fault

In this section, we’ll explain the main causes of the brake lamp fault warning and give solutions to them.

1. Faulty Brake Light Bulb

Usually, when bulbs become old, they tend to lose their bright light and become dim, and, in most cases, die out.

So when the bulbs have passed their useful life or span, the brake lights would cease to illuminate.

The Brake Lamp Bulb Fault message will appear on your dashboard to notify you of the problem.

This feature is put in place as a safety precaution so that you can fix the defect before you get involved in a rear collision accident.


Here, the idea is not to repair the faulty bulb but rather to replace it with a new one.

You can do this by carefully following the steps below;

  1. First, loosen the defective bulb’s case using a bolt.
  2. Carefully unplug the bulb and thoroughly inspect the bulb filament. (If the filament has dark smoke on it or is dark brown, then it is terrible)
  3. Proceed to replace it with a spare bulb or a new one you can get from an auto shop.
  4. Carefully close the bulb’s case and tighten it. And you’re good to go.

2. Bad Brake Switch

The brake lights are programmed to come on only when the brake pedals are pressed. The switch controlling the brake lights is located close to the brake pedal.

When you apply the brakes, the brake switch reacts to the pressure from your foot and activates the rear brake lights.

The ABS turns on when this switch isn’t working correctly. Unfortunately, such a situation could mean that any driver coming behind you won’t know that you are slowing down, which could cause a collision.


Fixing this issue would require a certain level of knowledge and probably a qualification as the brake switch is an essential part of the braking system.

We don’t advise that just anyone replaces the faulty brake switch. So if you don’t know how to work on cars, you should get an auto mechanic to fix it.

3. Blown Fuse

Another possible cause of the “Brake Lamp Bulb Fault” message could be a blown a fuse.

The fuse allows the brake lamp to function in the car. Therefore, when there is no issue with either the brake light switch or the bulb, the fuse is most likely the culprit.

A faulty fuse can make the lights fluctuate or go off completely.

Like all other fuses, the brake light fuse is found in the power distribution center, usually underneath the dashboard or under the hood.

If you’re unfamiliar with the term ‘power distribution center,’ It’s just a technical name for the fuse box.


Repairing a fuse wouldn’t be a permanent fix for this issue; therefore, replacing a damaged or faulty fuse with a new one is the best option. To do this, follow the steps below:

  1. First, switch the vehicle off to prevent electric shock.
  2. Next, use your vehicle’s owner’s manual to find the brake lamp’s fuse.
  3. Find the faulty fuse. The faulty fuse would have a dark brown color, and you would probably cut its wire.
  4. Simply remove the defective fuse and replace it with a new one.

After doing these steps, check that the problem’s been solved. And if this doesn’t fix it, you’d probably need an auto mechanic.

Also Read: Brake Light Blinking (Causes & How To Fix)

4. Wiring Problems

Again another possible cause of the “Brake Lamp Bulb Fault” warning is faulty wiring. Wires are responsible for all electrical connections, like all devices, switches, and sensors are connected through cables.

In this case, wires connect the brake lamps to the buttons, the brake pedals, and the fuse.

Thus, if a wire is cut, burnt, or loosely connected, it could disrupt the flow of electricity, causing the brake lamps not to function correctly.

Also, A short circuit in the wiring can cause the issue.


There Are three ways of fixing faulty wiring, and they are:

  1. You can replace the damaged wires or rewire them using the same cables (if their condition isn’t critical)
  2. Apply tape on exposed wiring.
  3. Make sure to tighten any loose connections and clean all terminals.

5. Faulty Relay Or Module

Now the brake module or relay sends information to the computerized braking system such that When you use the brakes, the data from the brake pedal is relayed to the central system, which stops the car.

The brake lamps also receive signals from the module.

A faulty brake relay could cause the brake lamp bulb fault message to appear on the dashboard. It could also cause brake failure and make the rear brake lights malfunction. In rare cases, it could lead to an engine shutdown for vehicles having the push start feature.


This issue is usually left to auto experts. If you have the proper tools and knowledge, you’d need to use a multimeter to troubleshoot the module and check if it is working.

If it turns out not to be working, you can proceed to replace it with a spare or a new one.

Also Read: Why Won’t My Brake Lights Turn Off (Causes & Fix)

6. Reduced Brake Fluid Level in the Brake Master Cylinder

The Master Cylinder is a vital component of the vehicle’s hydraulic system. It holds an incompressible fluid that creates a possibility for braking. Therefore, it is sometimes also referred to as the Master Cylinder.

When the brakes are applied, the pump pushes the incompressible fluid in the hydraulic brake line, which in turn causes the vehicle to come to a stop.

If the fluid level is low, there wouldn’t be enough pressure for the pedals to work with; thus, the brake lamps won’t come on.

Leakages can reduce the fluid level within the master brake cylinder, and they can also reduce after a certain period, resulting in braking problems.


This problem is easily fixed by adding more brake fluid to the reservoir, so its level is at the max. Also, you can consider replacing your brake pads as worn-out places could also lead to a reduction in the brake fluid level.

Brake Lamp Bulb Fault

Frequently Asked Questions – Brake Lamp Bulb Fault

What’s a Brake Lamp Bulb Fault?

The “Brake Lamp Bulb Fault” warning is displayed whenever there is an issue with your braking system that would cause your vehicle’s brake lamps to go off or even flicker.

Is It Safe to Drive With a Faulty Brake Lamp Bulb?

It is not safe to drive with a faulty brake lamp bulb as it can cause you to have an accident. You can also get a ticket for driving with a faulty brake lamp bulb. However, if you discover that your brake lights are faulty while still driving, you should activate your hazard lights to warn your fellow road users on time, especially while driving on an express road.

Is It Possible to Know if My Rear Brake Lamp Bulbs Are Working?

There are two simple ways to know If your rear brake lamp bulbs are working. The first is to drive your vehicle backward close to a wall and then hit the brakes, and if your brake lamps are working, you will easily notice a red light reflecting off the wall. You could also ask anyone around the vicinity to help you watch the rear of your car as you hit the brakes. The second method seems a whole lot easier.

How Much Would It Cost to Replace a Broken Lamp Bulb?

Replacing a damaged brake lamp bulb isn’t much of a hassle and is something almost anyone can do. It would cost around $10-$30 to purchase a brake lamp bulb.

How Do I Know if I Have a Low Brake Fluid Level Within the Master Cylinder?

To know if you have a low brake fluid level within the master cylinder, look for the brake fluid reservoir under the hood of your car. Most brake fluid reservoirs are opaque but allow you to confirm the brake fluid level label without opening the container’s cap. Nevertheless, if the container is not translucent, you might need to open the reservoir’s cap and use a level stick.

Conclusion – Brake Lamp Bulb Fault

When a problem results in the brake lamp bulbs going off, you receive a “Brake lamp bulb fault” warning message from your car.

The message is displayed due to either wrong or faulty wiring, faulty brake light switch, low brake fluid level, a faulty module, a faulty fuse, or even a damaged brake lamp bulb.

If you’re having this issue, it’s best not to ignore it because you wouldn’t even be aware of an incoming rear collision. And remember, if you feel you are not up to performing any of the repairs above, feel free to consult your mechanic.

Leave a Comment