Brake Light Not Working? What To Do Now

If your brake light isn’t working, pull over safely, switch on your hazard lights, and verify which light is out; then check the bulb or LED module, the fuse, and the brake-pedal switch. Replace a burned-out bulb or blown fuse on the spot if you can; if multiple brake lights are out or the new fuse blows again, you likely have a switch, wiring, or module issue that needs professional diagnosis. Driving with no working brake lights is unsafe and illegal in many places—avoid night or heavy-traffic driving until it’s fixed.

Immediate safety steps on the road

Before troubleshooting, reduce your risk of being rear-ended. These quick checks help you confirm the problem and keep you visible while you figure out a fix.

• Pull over somewhere safe and flat; switch on hazard lights.
• Use a reflective surface: back up near a window, garage door, or shiny storefront to see which brake light isn’t illuminating.
• Ask a passenger—or use your phone’s rear camera propped against a curb—to record the lights while you press the pedal.
• Check all three: left, right, and the center high-mount stop lamp (CHMSL).
• Lightly press the brake with the engine on; some cars only power the circuit reliably with ignition on.
• If you have no brake lights at all, avoid driving at night or in heavy traffic and proceed directly to repair.

These steps quickly confirm whether you have a single-bulb failure or a broader electrical issue, guiding your next move.

Quick diagnostic checklist (from easiest to more advanced)

Use this sequence to isolate the most common causes without wasting time or money. Stop when you find the fault.

1. Confirm which lamp(s) are out: one side, both sides, or only the center lamp. Pattern matters.
2. Check the brake light fuse(s): see the owner’s manual for location; many cars have separate fuses for left/right/CHMSL.
3. Inspect the bulb: for incandescent, look for a broken filament or dark spot; for LED, look for water ingress or dead segments.
4. Check the socket and connector: corrosion (green/white crust), melting, or loose pins can stop current flow.
5. Test the brake-pedal switch: if all brake lights are out and the shift interlock or cruise control also misbehaves, the switch is suspect.
6. Flex the trunk/hatch wiring loom while pressing the brake: broken wires at the hinge are common on hatchbacks and SUVs.
7. Verify ground: a bad ground can make the bulb glow dim or not at all; look for a loose or rusty ground screw near the lamp.
8. Unplug any trailer wiring module: shorts in aftermarket harnesses frequently blow fuses or disable the circuit.
9. Scan for body control module (BCM) codes: modern cars may log brake-lamp circuit faults; a basic OBD-II tool with body module support helps.
10. Check for recalls or technical service bulletins (TSBs): some models have known issues with lamp seals, switches, or BCM logic.

Working from simple to complex prevents unnecessary parts replacement and helps you decide if the repair is DIY-friendly or requires a shop.

How to replace a brake light bulb or LED module

Most incandescent brake bulbs take minutes to replace; LED modules can be more involved. Always match part numbers and protect fragile trim.

1. Gather parts and tools (see list below) and confirm the correct bulb type (common types: 1157/2057/3157/7443) or the specific LED assembly for your vehicle.
2. Access the lamp: from inside the trunk/hatch, remove trim clips or a small service panel; some vehicles require removing two or three exterior screws.
3. Twist out the bulb holder counterclockwise; gently pull the bulb straight out.
4. Install the new bulb: align pins correctly; avoid touching glass with bare fingers (use gloves) to prevent hot spots.
5. If LED-equipped and the vehicle uses a sealed module, remove the lamp assembly, swap the module or entire lamp per manufacturer procedure, and reconnect.
6. Inspect and clean contacts; add a tiny dab of dielectric grease to deter corrosion.
7. Test the brake lights before reassembling trim; confirm left, right, and CHMSL function.
8. Reinstall all fasteners and ensure weather seals sit properly to prevent leaks.

A careful replacement restores full brightness and prevents moisture intrusion that could trigger future failures.

Notes for LED-equipped vehicles

Many late-model cars use LED brake lights that don’t have serviceable bulbs. Here’s what to know before you start.

• The “bulb” is often an integrated LED board; you may need to replace the entire lamp assembly.
• Some vehicles require BCM coding or a specific initialization after replacing an LED lamp; a shop scan tool may be necessary.
• If only part of an LED array is out, it’s still typically a full assembly replacement, especially if moisture is present.

Checking the service manual for your exact model avoids surprises like coding requirements or hidden fasteners.

Tools and parts you’ll likely need

A small kit can handle most brake-light fixes at the curb or in your driveway.

• Replacement bulb(s) or LED lamp assembly matched to your VIN or bulb code.
• Fuses of the correct amperage (check the manual or fuse cover).
• Trim tool or flat plastic pry tool; Phillips/Torx screwdrivers; small socket set.
• Nitrile gloves and a clean cloth to handle bulbs and protect trim.
• Contact cleaner and dielectric grease for sockets and seals.
• 12V test light or multimeter for quick circuit checks.
• OBD-II scanner with body/BCM access (optional but helpful on newer cars).

With these basics, you can diagnose most issues and perform clean, reliable repairs.

Common causes and how to spot them

Brake light failures usually trace back to a handful of culprits. Recognizing the symptoms speeds up the fix.

• Burned-out incandescent bulb: dark or broken filament; other lights in the same housing still work.
• Blown fuse: multiple lamps out on one side or all brake lights dead; fuse element visibly broken.
• Faulty brake-pedal switch: no brake lights and cruise control/shift interlock glitches.
• Corroded socket or melted connector: intermittent or dim light, visible discoloration or green/white corrosion.
• Broken ground wire: faint glow, backfeeding through other bulbs, or flicker when other lights are used.
• Trunk/hatch loom break: works when the hatch is open, fails when closed; visible cracked insulation near hinge.
• Trailer harness short: repeated fuse blows; problem disappears when trailer module unplugged.
• BCM or coding issue: bulb good but circuit disabled; diagnostic trouble codes present.
• Wrong bulb installed: single-filament bulb in a dual-filament socket causing odd behavior.
• Aftermarket LED compatibility: bulb-out warning or no light due to CAN bus current monitoring.

Matching the symptom to the cause helps you choose between a simple part swap and deeper electrical testing.

Legal and safety considerations

Brake lights are a core safety system, and laws reflect that.

• Traffic laws in most regions require at least two functioning rear brake lights; violations can result in stops and fines.
• Annual or periodic inspections (where applicable) will fail for inoperative brake lights.
• Driving without brake lights increases rear-end crash risk and could affect fault or insurance claims after a collision.
• If no brake lights work, avoid driving at night or in poor visibility and use hazard lights only to pull over, not as a substitute while moving.

Fixing the issue promptly protects you legally and, more importantly, keeps everyone on the road safer.

When to call a professional

Some faults point to issues that are faster—or safer—handled by a technician with wiring diagrams and diagnostic tools.

• All brake lights out but fuses and bulbs are good.
• Fuses blow repeatedly, suggesting a short circuit.
• Moisture, cracked lenses, or melted connectors requiring resealing or replacement.
• BCM-related faults or the need for coding after LED lamp replacement.
• Broken wires in body harnesses or complex trailer-module integrations.
• Related warnings (ABS/ESC/cruise) after a switch or lamp issue appears.

Professional diagnosis can save time and prevent compounding electrical problems, especially on modern, networked vehicles.

Expected costs

Prices vary by vehicle and region, but these ballpark figures help set expectations.

• Incandescent bulb: $5–$15 each; DIY labor is minimal.
• LED lamp assembly: $150–$1,000+ per side, depending on model; labor 0.5–1.5 hours.
• Brake-pedal switch: $20–$75 part; $80–$200 installed.
• Fuse: $2–$10 each.
• Wiring repair: $120–$400 depending on location and complexity.
• Diagnostic scan/time: $90–$180 at independent shops; dealers may be higher.
• CHMSL: $20–$150 for bulb types; $100–$300 for LED versions.

Confirm parts with your VIN to avoid returns, and ask for a written estimate if a shop is doing the work.

Troubleshooting notes for modern vehicles

Today’s cars often monitor bulbs and manage circuits electronically, which can change how failures appear.

• BCMs may shut off a circuit when a short is detected, then restore it after the key cycles—intermittent symptoms can be electronic, not mechanical.
• OBD-II body codes (B-codes) can point to the exact circuit; a compatible scan tool saves guesswork.
• Hybrids/EVs still use a brake switch to command lamps regardless of regenerative braking; a failed switch can affect multiple systems.
• Auto-hold and adaptive cruise use the same signals; odd behavior there can hint at the root cause.
• Aftermarket LEDs may require CAN bus-compatible bulbs or load resistors; avoid resistors unless necessary due to added heat.

Understanding these behaviors helps prevent misdiagnosis and unnecessary parts replacement.

Simple prevention tips

A few habits can keep your brake lights reliable and bright year-round.

• Do a monthly two-minute light check using a wall reflection or a helper.
• Replace left/right bulbs in pairs so brightness matches.
• Use dielectric grease sparingly on sockets to deter corrosion.
• Avoid over-wattage bulbs that can melt housings; stick to the specified part number.
• Protect lamp housings from cargo impacts; secure loads in the trunk/hatch.
• Fix water leaks quickly; moisture kills sockets and LED boards.
• Choose quality, CAN bus-compatible LED replacements if upgrading.

Regular checks and quality parts dramatically reduce surprise failures and improve visibility.

Summary

If a brake light fails, prioritize safety, confirm which lamp is out, and check the simplest items first: bulbs, fuses, sockets, and the brake switch. Modern vehicles may add BCM monitoring and coding needs, especially with LED lamps. When symptoms are widespread or fuses keep blowing, seek a professional. Until you’ve restored full brake-light function, limit driving—being seen is non-negotiable for road safety.

Can AutoZone fix brake lights?

No, AutoZone does not typically fix brake lights by performing the installation; however, they will sell you the correct brake light bulb, provide guidance on how to install it yourself, and in some cases, offer assistance with simple, accessible bulb replacements by using their basic tools. For complex issues beyond a bulb replacement, such as a faulty brake light switch or wiring problems, you will need to consult a professional mechanic, and AutoZone can help you find one through their Shop Referral Program. 
What AutoZone can help with:

• Part Sales: They stock a variety of brake light bulbs and can help you find the right one for your vehicle. 
• Guidance: AutoZone staff can offer advice and instructions on how to replace the bulb. 
• Simple Installations: Some locations will perform easy, accessible bulb replacements as a courtesy when you purchase parts from them. Call ahead to confirm this service at your local store. 

What you need to do:

• Check Your Owner’s Manual: Your vehicle’s owner’s manual is the best source for information on how to replace the bulb. 
• Bring Your Vehicle: For a free in-store installation, visit your local AutoZone after confirming the service is available, and make sure your car is easily accessible for the task. 
• Use Their Tools: If they perform the installation, you can use their store’s basic tools. 

When to see a mechanic:

• Complex Replacements: If the light assembly is hard to reach or your vehicle requires tools beyond basic screwdrivers, a mechanic is a better option. 
• Persistent Problems: If the new bulb doesn’t fix the issue, or if your brake lights aren’t working at all, there may be a more significant problem, such as a faulty brake light switch or damaged wiring, which requires professional diagnosis. 
• AutoZone’s Referral Program: If the repair is beyond your skill level, AutoZone can help you find a qualified mechanic through their program. 

How much does it cost to fix a brake light?

Fixing a brake light can cost from under $10 for a DIY bulb replacement to several hundred dollars if the entire light assembly needs replacement, especially with complex LED systems. The final price depends on the vehicle, the type of failure (bulb vs. housing), whether you do it yourself or hire a professional, and your location. 
Factors influencing the cost:

• Type of failure:
  • Bulb replacement: The cheapest option, costing only a few dollars for the bulb itself. 
  • Light assembly replacement: More expensive, involving replacing the entire plastic casing, especially if it’s cracked or damaged. 
  • Wiring or switch issues: Can require more complex diagnostics and potentially costly repairs, such as replacing a brake light switch or harness. 
• Vehicle type:
  • Older cars with standard bulbs: Easier and cheaper to fix. 
  • Modern cars with LED lights: LED assemblies can cost significantly more, with some high-end units costing thousands. 
• Labor vs. DIY:
  • DIY: You can save on labor costs by replacing the bulb or even the housing yourself, as many are designed for easy removal. 
  • Professional service: Costs will include parts and labor fees. The price can vary significantly between dealerships and independent mechanics. 
• Location: Costs can vary by region, affecting parts pricing and labor rates. 

Typical cost ranges:

• DIY bulb replacement: A few dollars for the bulb. 
• Shop bulb replacement: About $30–$40 or potentially more for a dealer visit. 
• Full light assembly replacement: Can range from under $100 (e.g., aftermarket parts from junkyards or online) to over $500, depending on the car and parts. 
• Brake light switch replacement: Often around $100 to $133. 

Can you drive if your brake light is out?

No, you cannot legally or safely drive with a brake light out because it is a defective vehicle condition that can lead to a ticket or fine and is extremely dangerous, as it prevents other drivers from knowing when you are braking or slowing down. You should replace the bulb or get the light fixed as soon as possible to ensure your safety and avoid legal trouble. 
Legality

• Illegal: Driving with a non-functioning brake light is a violation of traffic laws in most places, including California, where all vehicle lighting equipment must be in good working order. 
• “Fix-it” ticket: While you might receive a “fix-it” ticket, which can be dismissed after you prove the light is repaired, you could also face a fine or points on your license. 

Safety Risks 

• Impaired Communication: Opens in new tabBrake lights are crucial for communicating with drivers behind you, letting them know when you’re slowing down or stopping.
• Increased Accident Risk: Opens in new tabA broken brake light increases the risk of a rear-end collision because other drivers won’t have adequate warning of your actions, especially at night or in bad weather.

What to Do

• Replace the Bulb: Replace the burnt-out bulb immediately. 
• Get It Fixed: If you can’t fix it yourself, get the light repaired by a professional. 
• Carry Proof: Keep a receipt or other documentation to show the police that you’ve fixed the defect if you receive a notice. 

What should I do if my brake lights are not working?

If a brake light is out, you should immediately pull over and park safely, turn on your hazard lights, and alert other drivers with hand signals. Then, safely check the vehicle’s bulbs and fuse. If these are okay, inspect the wiring and the brake light switch. If the issue isn’t a simple fix, you’ll need to have the vehicle repaired by a mechanic.
 
This video demonstrates how to check and replace a burnt-out brake light bulb: 57sMatherPEYouTube · May 22, 2025
Immediate Actions 

1. Pull over safely: Find a secure spot to park the vehicle as soon as possible.
2. Turn on hazard lights: This alerts other drivers to your vehicle’s issue and prompts them to keep a safe distance.
3. Use hand signals: Extend your arm to signal your intentions to stop or slow down.

Troubleshooting on the Spot

1. Check the bulb: Opens in new tabThe most common cause is a burnt-out bulb. Check the bulb and replace it if it’s blown. 
2. Check the fuse: Opens in new tabLocate your car’s fuse box (often under the hood or dash) and check for a blown fuse for the brake lights. Replace a blown fuse with one of the same amperage. 
3. Inspect the wiring and socket: Opens in new tabCheck the light bulb socket for corrosion or loose connections. Look for any signs of damaged or chewed wiring. 

This video shows how to diagnose issues with brake lights including checking the fuse and wiring: 36s1A Auto: Repair Tips & Secrets Only Mechanics KnowYouTube · Aug 6, 2020
When to Seek Professional Help

• If the problem persists: If replacing the bulb or fuse doesn’t fix the issue, the problem could be a faulty brake light switch, wiring damage, or a problem with the body control module (BCM). 
• For recurring issues: If fuses blow repeatedly or you’re unsure of the cause, consult a qualified mechanic or electrician. 

Why It’s Critical

• Safety: Brake lights are crucial for alerting other drivers when you are slowing down. 
• Legal Requirement: Driving with a non-functional brake light is often a traffic violation and can lead to a citation.