Why is My Brake Light On?

Nobody likes it when a warning light on the dash panel lights up. You may be tempted to ignore your brake light when it comes on, but this would be a potentially fatal mistake. If the brake light is on, your car is trying to inform you that there is some kind of problem with the parts of the brake system: the safety feature you use every time you drive. Avoid driving with the brake light on, this light is an indicator that you need to diagnose a potential braking issue.

Obviously, it is not advisable to drive around in a car that has faulty brakes. It is very common to ask yourself, “Why is my brake light on?” The good news is that it is relatively easy to discern what the problem might be, even if you are not experienced with cars.

My Brake Light is on, What Do I Do?

1. Start with the Parking Brake

This depends on when you notice the light. If you first notice the light when you turn on your car, you definitely don’t want to drive it until you figure out what the problem is. The very first thing that you should check is to ensure that the parking brake is completely off. Depending on your car, the warning light for the brake system may be the same as the warning light for the parking brake. This means that if the parking brake is engaged when the car comes on, the brake light automatically comes on to notify the driver.

This warning exists because if you drive around with the parking brake engaged, it can cause wear and tear to your brakes’ lining and this can cause them to wear out early.

So, the very first thing you should do is if the brake light is on when you turn on your car is to completely disengage the parking brake. If this does not fix the problem, then there is another problem with your braking system and you should not drive the car. (Also, in many newer cars the parking brake warning is distinct from the brake light.)

If the brake light came on while you were in the middle of driving, the first thing is not to panic.

What you should do is drive the car to a safe area to park, and then slowly engage your brake to stop the vehicle. Once you have done this, call a tow truck to bring the car to a mechanic or your own garage if you’re the type to work on your own car.

2. Check Your Brake Fluid

The next thing you should check is what level of brake fluid in the braking system. Oftentimes, the brake light may go on if the fluid is low. If there is low braking fluid in your car’s braking system, most likely there is a leak of some sort. This is a serious problem, because if there is no brake fluid in the hydraulic systems of your brakes, this means that the brakes won’t function.

A leak in your brakes hydraulic system should be taken very seriously. It is imperative to fix this or take your car to a knowledgeable mechanic quickly.

3. It Might Be the ABS

If you have checked that the parking brake is entirely disengaged and there appears to be no leak in the brake fluid system, then it is possible that the problem is with your anti-lock braking system (ABS). Again, it depends on the model of your car, but in some cars the brake light comes on to signal an issue with the ABS system. In newer cars, however, it’s likely that there is a dedicated ABS warning light.

Unfortunately, the only way to check whether or not the problem is with the ABS is to go and get the codes of your car read. AutoZone can scan your codes as part of our Fix Finder service, or you can do it yourself if you already have a scan tool. Having the codes read assists in determining what the actual problem is.

What Else Might it Be?

The vast majority of the time, the brake light is on because of one of the above three issues. But, there is a less likely chance that the problem could be with a brake sensor. Another possible issue may be with the wiring in the car. That is, the brake light going off can be a symptom of an electrical issue.

It is a good idea to familiarize yourself where all of the warning lights are located on your vehicle. There is no standardization for this, but you can figure out where all the lights are located by consulting your owner’s manual. After you turn on your car, for a split-second all of the warning lights should be illuminated. In that short time before they go off, you want to verify that all of the lights are indeed working. If you see that one of your warning lights is not going on during this check. you may want to get your car’s electrical system checked out.

While nobody likes to see any warning light go on, including the brake light, these lights are designed to prevent you from driving the car is something is wrong. Paying attention to the warning lights can save a life, even yours. These lights may be called “idiot lights” in jest, but they serve a vital purpose.

Make sure that your braking system is up to date. One of the most important things you need to ensure that you replace regularly are your brake pads. Remember, the efficacy of your braking system depends on these pads, so make sure that yours aren’t too run down. You can get the parts you need at your local AutoZone Store. If the job is too big for you, seek out one of our Preferred Shops to help you do the job.

Advice, how-to guides, and car care information featured on and AutoZone Advice & How-To’s are presented as helpful resources for general maintenance and automotive repairs from a general perspective only and should be used at your own risk. Information is accurate and true to the best of AutoZone’s knowledge, however, there may be omissions, errors or mistakes.

Be sure to consult your owner’s manual, a repair guide, an AutoZoner at a store near you, or a licensed, professional mechanic for vehicle-specific repair information. Refer to the service manual for specific diagnostic, repair and tool information for your particular vehicle. Always chock your wheels prior to lifting a vehicle. Always disconnect the negative battery cable before servicing an electrical application on the vehicle to protect its electrical circuits in the event that a wire is accidentally pierced or grounded. Use caution when working with automotive batteries. Sulfuric acid is caustic and can burn clothing and skin or cause blindness. Always wear gloves and safety glasses and other personal protection equipment, and work in a well-ventilated area. Should electrolyte get on your body or clothing, neutralize it immediately with a solution of baking soda and water. Do not wear ties or loose clothing when working on your vehicle.

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