What to do When Your Brake Lights Stay On

What to do When Your Brake Lights Stay On
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If you get honked at while stopped at a red light, it probably means the light is green, or that the driver is trying to get your attention to tell you that a brake light is out. Those are both easy fixes, but what about the opposite problem? If you’re wondering “why are my brake lights staying on,” just know it’s an annoying and potentially dangerous problem. Here’s how to get to the bottom of it.

What are brake lights?

Brake lights are important as a traffic safety device. When you step on the brake pedal to slow your vehicle, the brake lights on the rear of your vehicle illuminate to warn drivers behind you that you are slowing. Brake lights seem like an obvious requirement for any vehicle on the road, but they didn’t appear on cars until the 1920s.

Early drivers had simply adapted hand signals from riding horses, and that was generally good enough for the slow early horseless carriages. As speeds increased, hand signals became inadequate. Early movie star Florence Lawrence created devices for signaling turns and slowing in 1914, but they needed daylight to be effective. Edgar Walz Jr patented the electric turn signal and brake light in 1925, but neither would be standard for another decade.

Flash forward to the mid ’80s, the center high mount stop light, or third brake light, became federally mandated for all cars being manufactured. This brake light often appears at the top or bottom of the rear window to provide additional visual warning. It’s not just a gimmick either, as studies show the third brake light reduces rear-end collisions by 22%.

If a brake light bulb burns out, you probably already know how to affordably and quickly remedy the issue. When brake lights stay on, it can be a more complicated fix.

Why are my brake lights staying on?

The reason why brake lights stay on varies, but it’s likely an electrical issue and not that your brakes are constantly depressed. Still, start there just to be sure.

Pedal spacing and shoe clearance

Got big feet, or massive work boots? It could be that the accelerator and brake pedals are too close together for your footwear and/or driving style, allowing a slight depression of the brake pedal during cruising. Take a short drive while barefoot (which is completely legal in all 50 states) and note the position of the vehicle pedals in relation to your usual foot position. If there’s a lot of overlap, it’s time to “adjust the nut behind the steering wheel” and find a different driving position for your feet. At least this is a free fix.

Brake pedal switch

The brake pedal switch is located behind the brake pedal. When you push on the brake pedal, the switch takes the mechanical action and converts it to an electric signal that completes the brake light circuit, activating the brake lights. When the brake pedal switch ages and wears out, it can cause the brake lights to stay on. This is a rather simple swap if you have some tools and watch some YouTube videos to guide you.

Worn pedal spring

Ever notice how the brake pedal returns to its original position after you lift your foot? That return action is due to the pedal spring, and like the switch above, it can wear out due to constant use. A worn brake pedal spring doesn’t have as much tension, and the pedal doesn’t quite return to its proper position, which triggers the brake lights. Again, this is a quick and cheap repair, so there’s no reason to put this off.

Stuck brake pedal

Similar to the shoe clearance issue, you might have something besides your foot causing a stuck brake pedal. This means even when your foot is off the brake pedal, it is blocked from fully returning to the proper position. This issue can be caused by something on the floor, like a floor mat that slid under there as you drove. While you’re down there checking out the spring, have a look for anything out of place that could be pressing on the pedal or preventing it from returning all the way.

Pedal and switch alignment

The brake pedal switch is activated by a striker. If any of the components are out of alignment, the brake pedal striker and/or spring may not work. This could result in brake lights that don’t light up, or constantly stay on. If you see broken off pieces of unknown vehicle components on your floor mat, your issue is likely a severely misaligned pedal or switch.

Incorrect light bulbs

Head to your favorite auto parts store and make sure you grab the right bulbs for your tail lights. If the wattage or socket size is incorrect, the bulb is creating another brake light circuit issue that can cause all sorts of issues.

Body control module issues

Modern vehicles have a ton of electronic components (another reason to absolutely avoid a flood-damaged car), with groups of components in relays and modules. A common example is the body control module, which handles everything from interior lighting, door locks and air conditioning to rain-sensing wipers and even the brake lights. A failing BCM can cause brake light issues, including a stuck-on condition. If this is your problem, you should also see a service required light, and other electrical issues in other subsystems the BCM controls.

What to do if your brake lights are still on

First, if you notice your brake lights stay on, perform a careful (very slow) test drive, verifying that your brakes are functioning normally other than the brake lights. If you can stop normally, you’re good to start trying the steps above to solve your problem. If your home mechanic skills are limited to duct tape, then schedule an appointment with a dealership service center or local mechanic. Try to limit driving the vehicle, as this could endanger you and others on the road who may be confused by your always-on brake lights.

Conclusion

It can be annoying when brake lights stay on all the time, especially compared to the easy diagnosis of the more common burned-out brake light bulb. Take your time and make sure it’s not a driver issue, or simply an adjustment that can be performed for free. Then look into what possible components might be responsible, and replace as needed.

Frequently Asked Questions

Is it safe to drive your car with the brake light on?

No. Your brake lights advertise to everyone else that you are slowing down. Other drivers may suddenly adjust their driving accordingly, endangering them and everyone behind them. At best you are confusing other drivers, so get this one fixed ASAP.

Is it illegal to drive with brake lights stuck on?

This one varies by the state, but generally speaking, if it would fail a safety inspection, then it’s not legal on the road. Brake light function is checked at inspections, so odds are driving with the brake lights stuck on is risking a ticket.

How do I know if my brake light switch is bad?

If you have the brake lights stuck on symptom, you can narrow it down to the brake light switch by checking to see if your cruise control works. A faulty switch will also display an ABS warning light on the instrument cluster, and if you have the code read, it should be P0504. A mechanic replacing the brake light switch averages about $150.


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Disclaimer: The above is solely intended for informational purposes and in no way constitutes legal advice or specific recommendations.