Brake Light Basics: How to Test and Fix Your Car's Safety Signals

by AutoExpert   |  4 April, 2024

Share :

Brake lights are SO important. They keep you from getting rear-ended, and honestly, it's just rude to drive around with broken lights! Testing them a couple of times a year is a good idea, especially before it gets dark and rainy all winter.

The easiest way is to grab a friend (or bribe your kid with ice cream) and have them watch the back of the car while you stomp on the brake pedal. But hey, if you're alone, no worries! You can get fancy with mirrors or, honestly, a broom will do the trick. Just jam that handle against the brake pedal to hold it down, then walk around back and check. (Car in park, duh!)

Brake Light

Gotta Test ALL of 'Em

Don't forget, newer cars often have three brake lights – those two side ones, PLUS a middle one up high. Gotta make sure they're all bright and working!

Okay, What If They're NOT Working?

If none of your lights are coming on, chances are it's not the bulbs themselves. More likely, it's something electrical. But don't freak out – it might just be a blown fuse.

Brake Light

Fuses 101: Your car's got a ton of 'em, they protect those electrical circuits. Think of 'em like the circuit breakers in your house. If one goes out, bam, those lights stop working, but the rest of the car's fine.

Your car's manual will tell you where the fuse box is (usually tucked under the hood somewhere) and which fuse is for the brake lights. We're gonna need a "test light." Sounds fancy, but it's like a $5 thing at the auto parts store.

Brake Light

Here's the Test:

  • Car on (but not running).
  • Ground that test light (clip the wire to some metal on your car).
  • Poke the test light's pointy bit on each side of that fuse.

Does it light up? Good! Fuse is fine, bulbs are probably dead. But if it only lights up on ONE side of the fuse? That fuse is toast. Get a new one (has to be the same kind). Pop it in, test again, lights working? You're golden!

Brake Light

But...Sometimes It's More Complicated

If a new fuse doesn't do the trick, things get trickier. Could be a short in the wires... that's mechanic time, sadly.

Good News: Usually, It's Just a Bulb!

Replacing those is easy peasy. Again, that car manual is your friend. Usually you go in through the trunk. Unscrew the old bulb, careful, sometimes they're hot! If that little wire inside is broken or the glass is all black, yep, it's dead.

Get the right kind of new bulbs (your manual will say!), pop 'em in, and test again. Still nothing? Could be a broken socket, and again, that's probably a job for the pros.

Brake Light

One More Thing... The Brake Switch

So, you did the fuses, the bulbs, and still no lights. There's this switch down by your brake pedal that turns the lights on. If THAT'S broken, well... you gotta test it.

Same test light trick. Ground it, poke at the switch's wires while holding the brake down. Light up? Good. No light? Bad switch = mechanic visit.

Brake Light

Look, sometimes cars are weird, especially newer ones with fancy computers. If it's not these easy things, don't stress. A shop will get it sorted, but it's always good to try the simple stuff yourself first!

Top News

Recomended:

Car Limp Mode vs. EV Turtle Mode: Causes & 2026 EPA Updates - Photo
Others
Car Limp Mode vs. EV Turtle Mode: Causes & 2026 EPA Updates

Over the years, car companies figured out they needed to idiot-proof engines and transmissions. Limp mode is their answer. When something breaks, the car basically hobbles itself on purpose so things

AutoExpert
The Chevy Stovebolt Six: The 72-Year Legacy of the
Others
The Chevy Stovebolt Six: The 72-Year Legacy of the "Cast-Iron Wonder"

Nobody at Chevrolet actually named it the Stovebolt. When the inline six-cylinder showed up in 1929, gearheads took one look at those slotted bolts holding the pushrod covers and oil pan together and

AutoExpert
The Heavy Truth: Why Your 2026 Car Probably Has an Aluminum Hood - Photo
Others
The Heavy Truth: Why Your 2026 Car Probably Has an Aluminum Hood

Cars are getting heavier every year, and there's no sign of it stopping. The EPA has been tracking this since the early '80s, and new vehicles just keep adding more weight. Electric batteries,

AutoExpert
Michelin vs. Uniroyal: The Tire Satisfaction Report Is Out - Photo
Others
Michelin vs. Uniroyal: The Tire Satisfaction Report Is Out

Buying tires is one of those boring grown-up chores that nobody enjoys. It costs a lot, it feels confusing, and once they’re on the car, most people are just hoping they did not make a bad cho

AutoExpert
Toyota Tundra vs. The World: Which Truck Reaches 250,000 Miles? - Photo
Others
Toyota Tundra vs. The World: Which Truck Reaches 250,000 Miles?

People love to argue Ford vs. Chevy when it comes to trucks. But if the question is “which one is most likely to still be running at 250,000 miles,” the answer is… Toyota Tundra.

AutoExpert
100-Car Michigan Pileup: How to Survive a Winter Highway Nightmare - Photo
Tips & Tricks
100-Car Michigan Pileup: How to Survive a Winter Highway Nightmare

Over 100 cars just smashed into each other in Michigan. Don't let this be you.Winter driving already sucks enough without worrying about getting caught in one of those insane multi-car pileups

AutoExpert
Stop Driving Like It’s 1995: 5 Habits You Need to Quit in 2026 - Photo
Tips & Tricks
Stop Driving Like It’s 1995: 5 Habits You Need to Quit in 2026

Modern cars have changed. Your driving habits should too.Cars today are nothing like the ones people learned to drive on 20 or 30 years ago. They've got sensors everywhere, computers handling

AutoExpert
The Physics of the Flip: What Does That Tab on Your Rearview Mirror Do - Photo
Video
The Physics of the Flip: What Does That Tab on Your Rearview Mirror Do

It's not decoration; it's saving you from getting blinded at night.Most people have driven past that little tab on their rearview mirror a thousand times without really thinking about what

AutoExpert
Green is the New Gray: The Global Car Color Report Is Out - Photo
Others
Green is the New Gray: The Global Car Color Report Is Out

The car color situation is still depressing, but there's a tiny glimmer of hope.Car colors have been boring as hell for years now. Everyone just buys white, black, or gray like we're livin

AutoExpert
90 Years of the Chevy Suburban: History, Hollywood, and Specs - Photo
Others
90 Years of the Chevy Suburban: History, Hollywood, and Specs

Seriously, what's it going to take to kill this thing? The Suburban hit 90 this year. That's insane. Your great-grandparents could've bought one new. And here we are in 2026 and Chevy

AutoExpert