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!

Recomended:

From Workhorse to Status Symbol: How the Pickup Truck Quietly Took Over America’s Roads - Photo
Others
From Workhorse to Status Symbol: How the Pickup Truck Quietly Took Over America’s Roads

Picture a grocery-store parking lot in 1993: Tauruses, Accords, maybe a stray Explorer. Fast-forward to the same lot in 2026 and you’re surrounded by tailgates. Statistically that feeling is

AutoExpert
I Tried Ceramic Coating So You Don’t Waste $1,500: Here’s the Unvarnished Truth - Photo
Tips & Tricks
I Tried Ceramic Coating So You Don’t Waste $1,500: Here’s the Unvarnished Truth

I still remember the day I fell for the pitch.My hatchback had just come out of a basic wash, and the detailer, towel in hand, grinned like he’d discovered electricity. “If you reall

AutoExpert
EV Batteries Don't Just Die and Get Thrown Away. Here's the Surprisingly Cool Thing That Happens Next. - Photo
Others
EV Batteries Don't Just Die and Get Thrown Away. Here's the Surprisingly Cool Thing That Happens Next.

One of the most common questions people have about electric vehicles never really gets answered in car reviews or commercials: what happens when the battery eventually dies?It's a fair questio

AutoExpert
Kia Carnival Owners Need To Check This Recall Before The Next Family Drive - Photo
Car News
Kia Carnival Owners Need To Check This Recall Before The Next Family Drive

A minivan recall never sounds dramatic at first. It sounds like paperwork. A letter in the mail. A service appointment to squeeze in between school pickup, groceries, work, and the 47 other t

AutoExpert
Dealers Are Practically Paying You to Take a New Car Right Now (If You Know Where to Look) - Photo
Car News
Dealers Are Practically Paying You to Take a New Car Right Now (If You Know Where to Look)

If you've been waiting for the right moment to buy a new car, you might want to stop waiting.Fresh data from Kelley Blue Book, released this week, shows that new-vehicle prices moderated in Ma

AutoExpert
Is Your Car's Odometer Lying to You? Over 2 Million Vehicles on U.S. Roads Have Been Tampered With - Photo
Tips & Tricks
Is Your Car's Odometer Lying to You? Over 2 Million Vehicles on U.S. Roads Have Been Tampered With

When you buy a used car, you probably check the vehicle history report, poke around the exterior for dents, and maybe take it for a short test drive. That covers a lot of ground. But there is one scam

AutoExpert
Peugeot Brings Back The GTi With The Electric e-208 GTi - Photo
Car News
Peugeot Brings Back The GTi With The Electric e-208 GTi

Peugeot is bringing the GTi badge back, except now it’s attached to an electric hatchback instead of a noisy little gasoline engine. The production e-208 GTi will make its full debut on June 12,

AutoExpert
This Faux Land Cruiser Is Actually A Toyota Probox Underneath - Photo
Tuning
This Faux Land Cruiser Is Actually A Toyota Probox Underneath

Somehow, the Toyota Probox has become one of Japan’s favorite blank canvases for weird and surprisingly charming custom builds. The latest example comes from Goosfam, which looked at the hu

AutoExpert
Venuum Turned The Mercedes G-Class Into A Wild Four-Door Convertible - Photo
Tuning
Venuum Turned The Mercedes G-Class Into A Wild Four-Door Convertible

Mercedes-Benz is still working on its own G-Class Cabriolet, but Venuum clearly got impatient and built one first. The result is called the Mastodon V4, and it takes the already attention-hungry G-Wag

AutoExpert
Rare Michelotto Ferrari F40 Could Sell For Over $4 Million - Photo
Car News
Rare Michelotto Ferrari F40 Could Sell For Over $4 Million

Some Ferrari F40s spent their lives sealed away in collections. This one ended up in the hands of the people who built Le Mans race cars and came back far more extreme than Ferrari ever intended.T

AutoExpert