Brake Lights Won’t Turn Off

Brake Lights Won’t Turn Off: Reasons And Fixes

The brake lights of a vehicle should always remain in top-notch condition. This keeps you and other people on the road safe. The vehicle behind yours will notice the taillights while driving. That’s especially so if the brake lights won’t turn off at all. A switch is used by the brake lights to notify if the lights are on. The brake pedal is connected to the brake light switch. When you push on the brakes, the circuit is completed.

When there is an error with the circuit, the brake lights don’t turn off or on. However, the reason can be anything: from a broken brake pedal to an entire circuit failure. Due to some cause or the other, and if your car’s brake lights won’t turn off, it can be quite frustrating. You have to know how to diagnose and solve the problem to drive safely. This is what we’ll discuss today.

History Of The Brake Lights

The brake lights, otherwise known as tail lights, are a part of your automobile’s rear installation. Brake lights were first added to automobiles around the early 1900s.  But it took a while for regulations to mandate its installation. Until then, drivers would use hand signals to show cars behind them that they would turn or stop.

As more manufacturers included brake lights in their cars, the market saw a requirement that was established by 11 states in America in 1928. It was now mandatory for all cars to have a warning light for braking.

This was a response to higher volumes of tail-end crashes between vehicles in the night or with low visibility. It would take several more years before brake lights become mandatory across the US.

In 1974, the third brake light was a necessity in all cars in the US. As these were located higher, they were more visible to drivers behind, reducing the risk of collisions even further. One cannot overemphasize the importance of a sound brake light system. This is why it is good to understand how the system works, the failure modes, and how to confirm operationality.

On occasions, the brake lights won’t turn off or on in your car, but this seemingly minor malfunction could be the indicator of a bigger issue.

How Brake Lights Work

The majority of cars have a switch located under the dashboard on the driver’s end. It functions as a push button. The button connects with a part of the brake pedal level. The lever goes forward when you press the brake and lets the plunger extend. Then, the plunger activates the switch contacts, transmitting an electrical signal to the brake light system of the car. Finally, the lights turn on.

Cars built in the US before 2006 featured switches that directly controlled the electrical power transmission to the brake lights. Modern cars, however, are much more different. Today’s cars come with a computerized system named Controller Area Network (CAN) Bus system.

This system controls many of the car’s interior units as well as exterior lighting. It also helps reduce the clutter of wiring throughout the vehicle while enhancing fault checking and control of systems that operate through the ECU (Engine Control Unit).

The CAN Bus system controls the brake lights too. When you push the brake pedal, it sends an encoded signal to a control module. The lights receive power from these modules and illuminate. One major advantage of this system is that it’s easy to detect a failed brake light bulb.

A graphic display or warning light will be displayed on the instrument panel when a bulb fails. Not only does this show you that the light isn’t working, but in some cases, the display could also present the location of the failed bulb.

Why The Brake Lights Won’t Turn Off While Driving

Tail Light Repair Cost

It can be pretty annoying not knowing that the brake lights are on while you’re driving. These are some reasons behind this specific malfunction:

Faulty Brake Light Switch

Although it seems to actuate properly, the brake light switch could be faulty and thus, would not cut off the electrical signal illuminating the brake lights. Since automobile manufacturers design this switch to be reliable, this is an uncommon failure. Nevertheless, it can fail and force the brake lights to stay on continuously.

You can easily replace this switch if your body is flexible enough to reach the brake pedal. If not, see a mechanic. On some cars, a rubber or plastic bumper is connected to the brake light switch plunger. This bumper can fall off, fail, or be damaged beyond repair. Without a bumper, the switch plunger extended, keeping the brake lights on.

If the brake lights won’t turn off and you notice small rubber or plastic bits under your feet, the issue could be a failed bumper. This problem can be prominent in many models made by Mazda, Hyundai, and Honda.

Riding The Brakes

Even the lightest of pressures on the brakes could trigger the brake lights, illuminating them midway. While we drive, we tend to rest our left foot on the brake pedal (quite lightly). By doing this, you’re always ready to engage the brakes.

If your car features an automatic transmission and you tend to brake with your left foot, make sure you don’t touch the brake pedal, let alone rest your foot on it.

CAN Bus System Malfunction

Due to any hardware or software problem, the CAN Bus System could fail. The only solution is to get that diagnosed and fixed professionally by a mechanic or at a dealership.

Why The Brake Lights Won’t Turn Off While The Car Is Off

Brake lights can function even if the ignition and engine are turned off. So don’t be confused if you turn the engine off, hop out of the car only to see the brake lights are still on. Review 2 or 3 of the failure modes mentioned in the previous section. These conditions make the light stay on while everything else is shut down.

How To Check If Brake Lights Are Working Properly

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There are several methods that could help you check if the brake lights are still operational. And while it’s tempting to let the instrument panel tell you if it’s okay, you can never go wrong with a manual inspection. Here are a few of the easiest ways to do it:

1. Get A Helper

Call in reinforcements! Get a family member, friend, neighbor, or even a passenger to help you out. They can either press the brake pedal as you oversee while standing there, or you can do the footwork while they check the lights.

2. Storefront Window Reflection

Maybe you aren’t home but need to check if the brake lights are working. Locate a shopping center which offers parking right in front of the store. Use the storefront window of the outlet as a mirror. If permitted by car and foot traffic, back the car into a parking spot facing the front of the panel.

Keep your eyes on the rear view mirror as you apply the brakes. The brake lights should turn on if all’s well. This way, you can also inspect the rear emergency flashers and rear turn signals.

Repeat this process with the ignition off. Any location that doesn’t light up should be noted for future corrective measures. The turn signals shouldn’t work with the ignition off.

3. Garage Door

Naturally, the inspection process is easier if you’re at home. Pull the vehicle into the garage before closing the garage door. In the dark atmosphere, the brake lights (if on) should shine upon the garage door. You can notice that by pressing the brake pedal. This method can also be used in a covered parking garage.

4. DIY Tool

In case you don’t have access to a garage nor have someone to be the helper, you can make a DIY tool to check for life inside a brake light system. This tool will hold the brake pedal down and here’s how you make it:

Open the driver-side door. Press the brake pedal down by an inch with your left hand. Calculate the distance between the front of the driver’s seat and the pedal. Depending on the position of the seat, it will be around 18” to 22”. Find an old broom and cut it into a 1” x 2” shape. You can also use a trim board.

Wedge the back of the tool against the seat and use the tool to press down the pedal. You should have enough time to walk back and check the brake lights.

Why Is The Brake Warning Light On?

If the brake lights stay on for too long, the brake warning light will be illuminated. Most trucks, cars, and SUVs feature a wide range of warning lights. When the brake signal light lights up, it’s a sign that there’s something wrong with your car.

In this case, the issue has to be addressed immediately to protect riders from potential harm. Don’t panic if let’s say, the brake lights come on while you’re driving. Pull over to the side, and get a towing service to bring your car back home or to a professional. It’s important to not keep driving in that condition.

Similar to brake lights not turning off, the brake warning light might be illuminated due to a variety of reasons.

Brake Fluid

The brake fluid plays an important role in braking performance. Once the brake pedal has been pressed, pressurized fluid in the brake hoses and brake line forces the calipers’ pistons to apply force to the inner brake pads. As they are squeezed, the car slows down.

You can check the level of brake fluid inside the master cylinder.  This part is also known as the brake fluid reservoir. Find it on the driver’s side. Featuring a white or yellow plastic construction, the brake fluid reservoir shows you the ideal range of brake oil. Add more if the fuel level is too low. However, flush out the old brake fuel before adding a new one.

Parking Brake

Sometimes, the problem is right there in front of our eyes and we can’t see it. A super simple issue that keeps the brake lights on would be having the parking brake still engaged. Simply release the parking brake completely to fix the problem.

Brake Sensors And Pads

Over time, brake pads eventually wear out. Like any other car part, you have to replace them once they’re extremely worn out. Newer vehicles will notify you when the pads need to be changed. Your brake warning light being on might be the way it’s telling you that.

If the brake system warning light lights up the moment you turn the car on, it’s best not to risk driving it. Firstly, you will want to get that checked to make sure the parking brake has disengaged completely. After that, the brake warning light not turning off is usually indicative of a much more serious problem with the braking system. Turn the engine off and get the vehicle towed to a professional.

On events when the brake warning light is illuminated, your vehicle will not be as quick as normal – just a head’s up. This raises the chance of accidents on the road. Safely park the vehicle into a parking area or remove it from the traffic.

How To Fix Faulty Brake Light

Now, after realizing that the brake lights on your car aren’t working properly, you ask yourself what’s the next step. Fixing them, of course! For your own safety, let’s assume that the problem isn’t that severe and you can fix it by yourself. If this is one of those cases, these are some of the more common ways in which you can fix a bad brake light.

Fixing The Brake Pedal

Some of the most common causes why the brake light won’t turn off stem from a problem with the brake pedal. It probably got stuck in place or is pressing the switch slightly. Or, dirt and debris have accumulated on the brake light switch and pedal, preventing the lights from turning off.

If that’s the case, you can heave a sigh of relief as this is going to be an easy fix. All you need is an old toothbrush that you will use to scrub the points of contact between the pedal and the switch. Most of the gunk can be cleared through this. After that, pump the brake pedal multiple times to revert it to its original state.

Fixing A Broken Brake Pedal Stopper

The job of the stopper is to restrict the brake pedal from slipping too far down when it’s pressed on. Made of hard plastic, brake pedal stoppers can get worn out after time due to frequent use. When they get loose, they may be misaligned from their original position.

It’s best to replace the stopper if it’s loose or broken.  New ones aren’t that expensive and can be found easily in any car parts store or online. There are multiple video tutorials online showing you how you can install the stopper.

Fixing A Poor Electric Switch

The switch itself can be a problem on certain occasions. This is when you disconnect the negative terminal of the battery before trying something else.

Repairing The Wiring Of The Brake Circuit

Due to a short circuit in the wiring, the brake lights could refuse to turn off. This essentially means that despite the switch is open, the circuit is closed. Inspect the pigtail harness linked to the brake light switch. Any signs of damage, such as chew marks from rodents or burnt plastic stains, are a major problem.

We think it’s fine if you try to fix the wiring harness (give you have prior experience in this department). But keep in mind that every experienced mechanic will tell you that replacing an old harness with a brand new one is much more cost-efficient and the wiser thing to do.

Repairing The Damaged Brake Light Switch

The brake light switch, which is prone to errors itself, is an analog kind. This means that you have to manually press the device to close or open the circuit. After prolonged use, wear and tear could degrade the mechanism of this switch. Naturally, it malfunctions.

Don’t even bother attempting to repair the brake light switch. Chances are, you don’t own the right tools for the job. If you’re certain that the brake light switch is where the problem is originating from, discard it and install a new one.

The Risks Of Not Repairing The Always-On Tail Lights

You probably thought you could get away by blatantly ignoring the brake light issues. Perhaps, it won’t cause any damage – is what you think. However, this misconception could lead you to lose thousands of dollars in repairs. Plus, with a malfunctioning brake system, you put the lives of many people at stake.

Below are listed some of the reactions your car will produce when the brake lights won’t turn off and you won’t do something about it:

Drained Battery

Almost every time you leave the brake light on carelessly, this problem will arise. However, the issue runs deeper than the surface. The brake lights could stay lit after the engine has been turned off. That means if you didn’t see the tail lights being illuminated when you parked the car and left, upon your arrival, the battery could be drained.

But then again, the car would have to remain in that state overnight for the battery to be sucked dry.

Burnt Out Brake Light

When the brake lights won’t turn off, this burns through the brake light bulbs at a quickened pace. Sure, brake light bulbs can be found for cheap prices, but it’s still a hassle getting replaced every other week.

For this, you would have to take the tail light cover off and set the bulb before putting the cover back on. If performed too many times, damage may develop on the gasket restricting the entry of water into the light.

Damaged Brakes

Brake Lights Won’t Turn Off

Check if the pedal doesn’t retract all the way. If it doesn’t, it means that the pedal brakes are still engaged to an extent. In simpler terms, you have been riding the car’s brakes the whole time (unintentionally), and this doesn’t mean good news for the brakes.

Riding the brakes also means wearing down the pads associated with it, usually down to the metal. We recommend replacing the rotors for the best results. Worst case scenario, you will have to replace the brakes.

Get Pulled Over A Lot

It goes without saying that brake lights that refuse to turn off can be a road hazard. The person driving behind you won’t know when you plan on stepping on the brakes, setting the scene for a rear-end collision. When the police notice this unusual behavior, they will pull you over.

The first few times they will let you off with a warning. However, you could end up with a hefty fine for breaking traffic rules. A few too many tickets later you will get your license revoked.

Cause Serious Accidents

We mentioned multiple times how busted brake lights can confuse the driver behind you. The final situation? They rear-end your car. It’s not uncommon to find the brakes completely giving up on the driver mid-highway. After all, you have been riding on the brakes without a clue the whole time. Needless to say, all kinds of horrific accidents could occur as well.

Brake Lights Won’t Turn Off – Conclusion

If your car’s brake lights won’t turn off, then the most probable reason is a stuck or malfunctioning switch. Depending on the answer, you will either have to adjust the switch or change it. Ignoring the problem will only result in worse problems in the future. When you keep stacking up needed repairs, it only adds to your costs in the long run. Don’t put the lives of so many people in danger.

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1 Comment

  • Jaimedaniel Says

    After putting the car in the garage yesterday, I took out the key and the rear brake light is still on. I checked carefully, turned off the lights, took out the key, but still the light is on. I temporarily unplugged the battery and went to sleep, this morning I will continue.
    I did some research and the cause came from a faulty brake light switch, there was a rubber gasket where the switch fell off.

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