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Simple steps to troubleshoot and fix your faulty brake lights
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If your brake lights aren’t working, the problem is usually as simple as replacing the bulbs. Brake light bulbs go through a lot of wear and tear on the road because they get turned on and off so frequently, so you typically need to replace them every 4 years or so. However, a bad fuse, brake switch, or wire can also cause brake lights to go bad. In this article, we’ll cover everything you need to know about diagnosing and fixing your brake lights.

Section 1 of 4:

Common Causes & Solutions

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  1. Sometimes, the most mundane explanation is the most likely. Brake light bulbs burn out the same exact way that normal lightbulbs can burn out. In fact, brake lights go out more often than normal lights because the roughest wear and tear for a lightbulb is turning it on and off, which happens dozens of times for a brake light every day that you drive.[1]
    • If one of your bulbs goes out, it’s a good idea to just change all of the brake light bulbs. They tend to go out around the same time.
    • Signs this is the issue: Either one of the lights goes out, or the lights go out at different times. This is also likely to be the case if it has been 4-6 years since your brake lights last died.
    • The fix: Find a bulb designed for your specific make and model (Powerbulbs has a neat bulb finder here). Then, pop the trunk, remove the fasteners holding the light cover in place, and replace the bulb.
  2. Basically every electrical component in your vehicle has a dedicated fuse, and it’s possible the fuse for your brake lights is blown. Find the fuse box in your engine bay (it’s normally in a covered box close to the steering wheel). Remove the cover and locate the fuse dedicated to your brake lights. Remove it and test the fuse with a multimeter to see if it’s dead.[2]
    • The fuse layout for your vehicle is either in your manual or on your manufacturer’s website.
    • If this happens repeatedly, it’s a big sign that either you’re using the wrong bulbs for your vehicle, or the socket itself is bad.
    • Signs this is the issue: Both of your brake lights go out at the same time. You may also have an electrical failure indicator pop up on the dashboard.
    • The fix: If the fuse is dead, purchase a replacement fuse designed specifically for your vehicle’s make and model. Then, insert the fuse in the dedicated fuse slot and you’re good to go!
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  3. The brake light switch is the on/off button that triggers the brake lights to come on when you depress the pedal. If the fuse for that switch goes out or the switch’s wiring fails, the brake lights won’t turn on when you press the pedal.[3]
    • Signs this is the issue: The brake lights come on intermittently when you press the pedal, neither brake light comes on, and/or your lights aren’t more than 1-2 years old.
    • Some older vehicles have an analog switch, so there may not be a fuse to check at all.
    • The fix: Check the fuse for the brake switch to see if it needs to be replaced. If it doesn’t, see a mechanic. They’ll find the problematic wire and replace or repair it.
  4. None of the electrical components in your vehicle work without being grounded. In most vehicles, every component is connected to the metal frame of your vehicle (the current goes through the frame and down to the rubber). If the ground for your brake light switch is disconnected or faulty, your brake lights won’t come on.[4]
    • Signs this is the issue: You’ve checked the fuses and bulb and your brake lights are still unresponsive. This may also be the cause if you’ve got other electrical issues, since many ground wires feed to the same part of the frame.
    • The fix: This is kind of a whacky problem to diagnose at home, so see a mechanic. They’ll re-ground the component.
  5. There are wires running from your bulb to the brake switch, the switch to the fuses, and the fuses to the bulbs. In other words, there are a lot of wires. If one of them is damaged, it can keep your brake lights from coming on.[5]
    • Signs this is the issue: You’ve encountered squirrels or mice around or inside of your vehicle (they like chewing on wires), and the brake light warning symbol pops on.
    • The fix: See your mechanic. They’ll find your faulty wire and replace it for you.
  6. On some vehicles, the brake lights are wired to the same fuse and circuit as your turn signal lights. In other words, if a turn signal fuse blows or a turn signal wire is damaged, your brake lights won’t work either.[6]
    • Signs this is the issue: Your turn signals are also not turning on.
    • The fix: Drive over to your mechanic. They’ll find the source of your electrical woes and repair it.
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Section 3 of 4:

Risks of Driving with Broken Brake Lights

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  1. Brake lights are arguably the most important safety component on your vehicle after the brakes themselves. They signal to drivers behind you that you’re slowing down, and without that indicator, the odds of an accident occurring grow exponentially. If you want to keep your insurance and repair costs low, get your brake lights fixed.[8]
    • It’s worth noting that most drivers do not look at the ground to take cues on when to slow down. They subconsciously look for brake lights. If they don’t see brake lights, it’ll take much longer for them to realize what’s happening.
  2. For complicated reasons that are kind of difficult to explain, the brake light switch is connected to your transmission, which controls the gears. Now, on some cars, the transmission will “listen” to that switch instead of the engine when it comes to appraising what gear you need to be in. So, if the switch is bad, you may have trouble shifting while you drive. This is not only dangerous but bad for your engine.[9]
    • This problem seems most common in cars made between 2005-2015, but there are still a few manufacturers that configure their transmission this way.
  3. If there’s fog, heavy rain, or snow, your brake lights play an important role in the ecosystem of the road by providing key information to other drivers. For one, it signals to drivers far away that they’ll need to slow down soon. On top of that, it helps other drivers conceptualize how far away from things they are by giving perspective.[10]
    • Without your brake lights, you’re making it much more difficult for the drivers behind you to operate their vehicles safely when the weather is terrible.
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Expert Q&A

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  • Question
    How do I change the brake lights of my car?
    Jason Shackelford
    Jason Shackelford
    Auto Technician
    Jason Shackelford is the Owner of Stingray Auto Repair, a family owned and operated auto repair shop with locations in Seattle and Redmond, Washington. He has over 24 years of experience in auto repair and services, and every single technician on Jason’s team has more than 10 years of experience.
    Jason Shackelford
    Auto Technician
    Expert Answer
    For many vehicles, you will find an access panel located inside the trunk. To replace the brake lights, first remove this panel. Following this, you can typically pull out the light assembly from within the trunk and easily remove the bulbs by gently popping them out.
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About This Article

Jason Shackelford
Co-authored by:
Auto Technician
This article was co-authored by Jason Shackelford and by wikiHow staff writer, Eric McClure. Jason Shackelford is the Owner of Stingray Auto Repair, a family owned and operated auto repair shop with locations in Seattle and Redmond, Washington. He has over 24 years of experience in auto repair and services, and every single technician on Jason’s team has more than 10 years of experience. This article has been viewed 18,707 times.
8 votes - 62%
Co-authors: 4
Updated: November 10, 2023
Views: 18,707
Categories: Car Lighting
Thanks to all authors for creating a page that has been read 18,707 times.

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