Brake Lamp Bulb Fault Problem; Causes and Solutions

The brake lamp is a very important part of cars. The other drivers that coming behind you can notice that you are braking. They will be on and people will notice and make a brake after you. So, if there is any problem with your brake lamp, it is a very important safety problem in terms of the traffic. You need to take care of this issue as soon as possible. Here will explain all the aspects and general problems and solutions to the brake lamp bulb fault. So, you will be able to solve this problem with this guide. Also, you can find information about how much it costs to solve these general problems.

What is Brake Lamp Bulb Fault?

Brake Lamp Bulb Fault.
Image Source: Freepik.

In different modern cars such as Ford Focus and other cars, you can have a dashbıard warning that you have a brake lamp bulb fault. This may seem a very basic problem but it can indicate different kinds of problems with the electrical and the brake system of your car. But you can be sure that you are not the only driver who you get this fault.

First of all, it is a very important problem that you need to solve. This indication on your dashboard states that your brake lamp does not work well. And this is a very big traffic safety problem.

Think about a situation in that you are braking and decelerating. It will be very hard for the other drivers coming behind you that you are braking and stopping. And because of this, they can press the pedal very late and can cause very big damage.

It is also very hard to understand that you have a problem with the brake lamp of your car. Because you can not see the brake lamp and it is only activated if you press the brake pedal. But modern cars give an attention signal that you have a problem with your brake lamp.

How Does a Brake Lamp Work?

It will be much better to understand how does the brake lamp system work with the brake system of your car. You know that once you press the brake pedal, the brake lamps will on. These brake lamps inform the other drivers that you are decelerating right now.

First of all, it is a complete electrical system. There are switches and electrical connections that make it possible to work.

There is an electrical connection between the brake lamps and the battery of your car. Once you press on the brake pedal, the brake switch connects that electrical connection that makes on your bulbs. Once you depress the brake pedal, the switch opens and cuts the electrical connection between the battery and the brake lamp.

But we need to understand that the brake system of a car is a very complex system. There are relays that electınically control the different hydraulic systems and electromechanical systems when you are braking to provide much more effective braking. So, there can be an external problem that affects the brake lights.

This is the general working principle of brake lights.

Common Causes and Solutions of “Brake Lamp Bulb Fault”

There are different common causes of this problem that you are facing with your car. So, you need to know and apply the different solutions. These problems are generally;

  • Faulty lamps.
  • Brake switch problems.
  • Blown fuses.
  • Wiring problems in the system.
  • General brake system problems.

Check the general faults and the general solution tips below to understand how to solve this problem.

Faulty Lamps

Maybe this problem is caused by a very basic blown lamp. Inside the bulb of the lamp, there is a tungsten connection. Electric pass through this tungsten connection to glare. So, if the connection is broken, the brake lamp will not work properly.


  • First of all, you need to detach the bulb case on the back side of the car. Do not forget that you have two bulbs and you need to check two of them.
  • Check the filament if you can see about disconnection or rip-offs. If it is disconnected, the lamp is the problematic part of this problem. Also if it blew, you will see a dark brown color on the glass of the lamp.
  • If you have a new bulb, plug this into the socket.
  • Attach the cover that you unbolt before the application.
  • Check if the “brake lamp bulb fault” caution is gone.

Cost: You can do this operation by yourself. And the only cost is the new lamp cost. You can find both aftermarket and OEM brake lamps from $5-15 according to the brand of your vehicle.

Brake Switch Problem

brake lamp switch.
Image Source: Calleschopperdelar.

Another common problem can cause this fault. If there is a problem with your brake switch, you need to inspect it. And if the problem is with the switch, you need to replace it. But if you are not familiar with the electrical connections and car treatment, we recommend you bring your car to a car electrician expert to make this replacement.

Cost: Brake switches are not generally very high price parts. They are very basic electrical connectors. According to the brand and model of your car, you can find switches for around $15-20. And for the replacement, you may probably pay around $30 to the expert.

Blown Fuses

Fuse box in a car.
Fuse box in a car. Image Source: Carfax.

In electrical connections, we use fuses for the safe connection of the different electrical parts. And between the electrical connections of cars, there are fuses that connect the battery with the electrical applications. There is a metal wiring inside the fuse that will disconnect the electricity in the case of any high voltage and dangerous electrical current. And if they disconnect, you need to change the fuse with the new one.

You need to know that, there are electrical fuses for different ampere values. These ampere values can change between 5-10 A. And you need to buy the correct one for your brake lamp.

Solution: If you are not experienced in electrical applications, we recommend you bring your car to an electronic expert.

  • For safety, switch the car engine off to prevent any electrical shocks.
  • Find the fuse box of your car. Fuse boxes are the systems that include all the fuses that your car has. In general, the fuse boxes are around the driver console.
  • Check the fuses and find the burnt fuse. You can understand the severed connections in the fuse.
  • Change this fuse with the new one.
  • Close the fuse box.
  • Check if the problem is solved.

Cost: Fuse is a very basic part that you can easily find for $1 or $2 per part. But you need to take care of finding the correct fuse for your car. And you will be able to find and apply the correct one for your car. And if you are not able to replace it, you will probably pay around $20-30 to the expert.

Wiring Problems

As you understand that there are different wirings and connections that are connecting the different electrical systems in cars. And these wirings are generally passed between the cushioning and the steel structures. So, examining these wiring systems requires a professional inspection. And if you are not professional in car wiring applications, we recommend you bring your car to other professionals.

Professional people probably look for any connection problems in the wiring of the car. And also they will look for any problem or damaged section that the wiring system has.

Cost: In terms of the cost, saying an exact price for this problem is not possible actually. But you will pay a minimum of $100 for the general wiring treatment for your car.

General Brake Problems

Master cylinder can cause brake lamp bulb fault.
Master cylinder diagram. Image Source:

Maybe, you have a general problem with your brake system. The general problems may arise from different problems in your system.

For example, if the brake fluid decreases in the master cylinder of your brake system, this can cause the “brake lamp bulb fault” problem for your car. So, you need to take your car to a mechanic that specialized in brake systems.

And also, you may have problems with the brake relays in the ECU systems. These relay connections are very important for high-technology electromechanical braking systems. Once you press the brake pedal, the ECU systems will activate the hydraulic systems, pumps, and cylinders to make an effective brake. This control takes place with the relays on the ECU systems.

If there is a problem with the relays, it is a very deep topic. You need t bring your car to the service. The problems with ECU systems are only solved with these systems in general.

Do Not Undersee the Problem!

It may seem a very basic problem to you. But it can cause very bad consequences. And it is illegal to drive without brake lights. So, as you see above it will not cost so much money if there is no big problem with your brake system.

Last Words on Brake Lamp Bulb Fault

So, as you see above, you can see there are different kinds of brake lamp bulb fault causes that you need to consider. And we gave the general things that you need to apply for your car. So, it will be very easy to solve this problem with this guide.

If you experienced the same problem, please leave your experiences and how did you solve it. Your feedbacks are very important to us.

You can also find other related topics about car maintenance at!

Oil System Cleaner – Best Ones to Extend Oil Life

Is Aftermarket Catalytic Converter Loud? OEM and Mufflers

Speedometer Cable in Cars – Everything to Know

Exhaust Back Pressure Sensor – Explanation and Costs

Brake Hold System Problem – Common Causes


What does brake lamp bulb fault mean?

It means you have a problem that causes the brake lights at the back of your car not to work. There are different kinds of causes of this problem that you need to consider. The causes; are faulty brake lamps, blown fuses, wiring problems, and other brake problems. You can make a diagnosis to find the common cause of this problem.

Can I drive with a brake lamp bulb fault?

Yes, you can drive. But do not forget that it is a very big risk to drive in traffic without brake lights. Because the drivers at the back side of you will not notice that you are braking or not at that time. So, it is very important to take care of this problem. And also, you can face paid penalties without driving brake lights in different states.

What causes brake light failure?

As we stated above in the article, there are different causes of this problem. The first one is the faulty brake lamp. Check if the brake lamps are blown or not. And also check the brake switch and brake lamp fuse. If there are problems with these parts, you will probably get this problem.

Is it expensive to fix the brake light?

In most cases, no. If you do not have a major problem with your brake system that causes brake light problems, you have probably a problem with the electrical connections of your car. And changing the electrical systems will not be expensive for you. You will probably pay around $50 for all the repairs.

Can I fix a brake light myself?

It depends on the cause of the problem. If you have a problem with the wiring system of the brake light and a general brake problem, probably you will not able to solve this problem. But if the problem is the brake switch, brake fuse, or brake lamp, you can solve this problem by yourself. But you need to diagnose the root cause of the problem that you are facing.

How long do brake light bulbs last?

In general, they last around five to six years. If you buy the OEM part, they will last up to 10 years. But if you buy the aftermarket ones, you will change it maybe for 4-5 years.

How much does it cost to change a brake light bulb?

For most car models, you can find both aftermarket and OEM brake lights for around $5-10. And if you have a basic toolbox that has essential tools, you can change the light bulb by yourself. For labor, you will also pay $10-20 according to the model. So the total cost will be around $20-30.

Uğur Uygun

Hello everyone, I am Uğur. I am a mechanical engineer who has experience in different R&D departments of HVAC companies. With my best friend, I decided to build this website to share out knowledge and experience. And also, I am interested in automotive. So, I am writing about automotive and automotive-related articles here. Sharing my knowledge and experiences on these topics is a very big pleasure for me. I am willing to answer all of the questions people have about these topics.

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