Is There a Fuse for a Brake Light Switch?

Yes—on almost all vehicles, the brake light switch (or the stop-lamp circuit it feeds) is protected by a fuse. Depending on the make and model, this fuse is typically labeled STOP, BRAKE, STOP LAMP, or CHMSL and is found in the interior fuse box or under-hood fuse/relay center. On many late-model vehicles, the brake lamps are controlled by a body control module (BCM), which is still protected by a fuse even if the switching is electronic.

How the Brake Light Circuit Is Usually Protected

In traditional setups, battery power flows through a dedicated fuse to the brake light switch on the pedal, then on to the brake lamps. In newer vehicles, the brake pedal position may be read by a sensor feeding the BCM, which then powers the lamps via a separate fused output. In both cases, a blown fuse can disable the brake lights entirely, and repeated fuse failures typically indicate a short or wiring fault.

Common Fuse Labels and Where to Look

Automakers use different labels and locations, but there are predictable patterns that help you find the right fuse without guesswork.

• Labels: STOP, STOP LAMP, BRAKE, CHMSL (center high-mount stop lamp), TAIL/STOP, TRLR STOP (trailer stop-lamp).
• Locations: Interior fuse box (under dash, driver’s side kick panel, glovebox), side-of-dash panel, or under-hood fuse/relay box.
• Amperage: Commonly 10–20A for stop lamps; trailer circuits may use higher values and separate fuses.
• Modern twist: Some vehicles integrate “electronic fusing” within the BCM; the circuit is still protected but may not use a replaceable blade fuse for every output.

If your owner’s manual references a STOP/STOP LAMP fuse, check that first. If the manual points to BCM-controlled stop lamps, you may also need to check BCM power fuses and related outputs.

Symptoms: Fuse vs. Switch vs. Wiring

Distinguishing a blown fuse from a failed switch or wiring fault can save time and prevent repeat failures.

• Blown fuse: All brake lights out at once; fuse looks melted or open; often follows a short (e.g., damaged bulb socket or trailer wiring).
• Bad switch/sensor: No brake lights, plus related features misbehave (can’t shift from Park on some vehicles, cruise control won’t disengage, ABS/ESC warnings in some cases).
• BCM/output fault: No brake lights even with a good fuse; scan tool shows DTCs; other lighting anomalies present.
• Partial outage: Only the high-mount stop lamp or only the left/right lamp fails—often a bulb, socket, or localized wiring issue rather than the fuse.

Use these clues to decide whether to start at the fuse, the pedal switch/sensor, or the lamp assemblies and harness.

Quick Diagnostic and Fix-It Steps

The following procedure provides a safe, systematic way to verify whether a fuse is responsible and to correct the issue without creating new problems.

1. Identify the correct fuse: Check the owner’s manual or the fuse-box cover for STOP/STOP LAMP/CHMSL/BCM labels.
2. Inspect and test the fuse: Pull the suspected fuse; look for a broken element. Confirm with a multimeter or test light.
3. Replace only with the same rating: Insert a new fuse of identical amperage. Using a higher rating risks wiring damage and fire.
4. Test the lights: Press the brake pedal and verify all stop lamps illuminate, including the high-mount lamp.
5. If the new fuse blows immediately: Inspect bulbs and sockets for corrosion or shorted contacts; check harnesses near trunk hinges, trailer connectors, and areas with recent work.
6. Check the switch/sensor: Verify 12V supply at the brake switch; confirm output when the pedal is pressed. If no output with good power and ground, replace the switch/sensor.
7. For BCM-controlled systems: Scan for body module DTCs and verify BCM stop-lamp output status; inspect BCM power and ground fuses.

These steps isolate whether the failure is a simple blown fuse, a faulty switch/sensor, or a deeper wiring or module issue, ensuring you fix the root cause rather than just the symptom.

Special Cases and Practical Tips

Some vehicles add complexity, especially with towing packages or advanced electronics. Knowing the exceptions can prevent misdiagnosis.

• Two-fuse setups: One fuse may feed the brake switch/ECU/cruise control, while another feeds the actual lamp circuit.
• Trailer wiring: Separate trailer stop-lamp fuses can blow independently; a shorted trailer harness is a common culprit for repeated fuse failures.
• CHMSL separate: The high-mount lamp may be on its own circuit; if only the CHMSL works (or doesn’t), check for a dedicated fuse and ground.
• Cold-weather and water ingress: Moisture in lamp housings or corroded sockets often causes intermittent shorts and blown fuses.
• Brake-shift interlock: If you can’t shift out of Park and brake lights are out, suspect the switch or the fuse feeding it.

When in doubt, consult the wiring diagram for your exact year, make, and model; it clarifies whether the fuse protects the switch directly or a BCM that controls the lamps.

Bottom Line

There is almost always a fuse protecting the brake light switch and/or the stop-lamp circuit. Start with the STOP/STOP LAMP fuse in the interior or under-hood fuse box, verify the brake switch operation, and check for BCM involvement on newer vehicles. Replace any blown fuse with the correct rating and address underlying shorts—especially in bulbs, sockets, and trailer wiring—to prevent repeat failures.

Summary

Most vehicles have a dedicated fuse for the brake light switch or the stop-lamp circuit, commonly labeled STOP, BRAKE, or STOP LAMP and located in the interior or under-hood fuse box. Newer cars may route control through a BCM, but the circuit remains fuse-protected. If brake lights are out, check and replace the appropriate fuse with the same amperage, test the brake switch/sensor, and inspect for shorts in bulbs, sockets, and wiring—particularly trailer connectors—before concluding the repair.

How to tell if a brake light fuse is blown?

To tell if your brake light fuse is bad, you can either visually inspect it by pulling the fuse and checking for a broken wire or cloudy appearance, or use a 12-volt test light to check for continuity. A bad fuse will have a broken internal connection, which you’ll see as a missing wire in the fuse’s clear window. With a test light, if it illuminates when touched to both sides of the fuse while the brake pedal is pressed, the fuse is good; if it only lights up on one side or doesn’t light up at all, the fuse is blown. 
Visual Inspection

1. Locate the Fuse Box: Find the fuse box, usually located under the hood or on the passenger side kick panel. 
2. Find the Brake Light Fuse: Consult your car’s owner’s manual to identify the specific brake light fuse. 
3. Remove the Fuse: Use the fuse puller (often found in the fuse box) or needle-nose pliers to carefully remove the fuse. 
4. Inspect the Fuse: Hold the fuse up to a light and look closely at the internal wire. 
5. Determine if it’s Blown: A blown fuse will have a visible break in the wire, and the connection might appear cloudy or burnt. A good fuse will have an intact, continuous metal line. 

Using a Test Light

1. Power On: Turn the car’s ignition on and press the brake pedal. 
2. Attach the Test Light: Connect the ground clip of your test light to a metal part of the car’s body. 
3. Test the Fuse: Touch the tip of the test light to each of the two metal terminals on top of the fuse. 
4. Analyze the Results:
   • If the light illuminates on both sides: The fuse is good and has continuity. 
   • If the light illuminates on only one side or not at all: The fuse is bad and needs to be replaced with a new one of the same amperage. 

Important Considerations

• Other Issues: If a new fuse also blows, it could indicate a short in the wiring or a faulty brake light switch, requiring further diagnosis. 
• Same Amperage: Always replace a blown fuse with a new one of the exact same amperage rating to prevent damage to the electrical system. 

Why am I not getting power to my brake light switch?

A faulty brake light switch can cause symptoms such as brake lights not working or staying on constantly, the gearshift being stuck in park, cruise control not functioning, and dashboard warning lights like the check engine or ABS light. You may also experience a problem starting your car if it has a push-button start system. These symptoms occur because the brake light switch needs to be functioning correctly to complete the electrical circuits for your brake lights, cruise control, and gear selector.
 
This video explains the symptoms of a bad brake light switch: 55sStudent LessonYouTube · Oct 26, 2023
Common Symptoms of a Faulty Brake Light Switch

• Brake Lights Don’t Work: When you press the brake pedal, the lights don’t come on. 
• Brake Lights Stay On: The brake lights remain illuminated even when the pedal is not pressed, potentially draining your battery. 
• Stuck in Park: In automatic transmissions, you can’t shift out of the “Park” position. 
• Car Won’t Start: Vehicles with a push-button start require the brake pedal to be pressed to start the engine. 
• Cruise Control Malfunctions: The cruise control may fail to set or might disengage unexpectedly. 
• Illuminated Dashboard Lights: Warning lights for the ABS or traction control system may come on. 

What You Can Do

1. Check the Fuse and Bulbs: Opens in new tabBefore assuming the switch is the problem, check for a blown fuse or burned-out brake light bulbs. 
2. Inspect the Switch: Opens in new tabThe switch is located near the top of the brake pedal. You can visually inspect it for any damage or misalignment. 
3. Use a Multimeter: Opens in new tabA multimeter can be used to test the switch for electrical continuity, confirming if it’s faulty. 
4. Replace the Switch: Opens in new tabIf the switch is confirmed to be bad, it can be replaced by disconnecting the wiring harness and installing a new one. 

This video shows how to replace a brake light switch: 58sthomas brianYouTube · Apr 14, 2016

Where is the fuse for the brake light switch?

The location of your brake light switch fuse varies by vehicle, but it’s commonly found in the fuse box under the hood or inside the cabin, near the dashboard, as indicated by the owner’s manual. To find it, locate your vehicle’s fuse box(es), open the cover, and look for a fuse labeled “brake light,” “stop light,” or a similar term.
 
This video shows how to find and remove the brake light fuse in a Honda Civic: 25sElectrical Car Repair LIVEYouTube · Aug 2, 2019
Steps to find and check the brake light switch fuse:

1. Consult your owner’s manual: This is the most reliable way to determine the exact location of your fuse box(es) and the specific fuse for the brake lights. 
2. Locate the fuse box: Your vehicle may have more than one fuse box. Common locations include under the hood, usually on the driver’s side, or inside the passenger compartment near the dashboard. 
3. Identify the correct fuse: Open the fuse box and look for the fuse labeled as “brake light,” “stop light,” or something similar. 
4. Remove the fuse: You can often pull the fuse out by hand, but a fuse puller, a small tool often found in the fuse box itself, can be helpful. 
5. Check the fuse: Hold the fuse up to a light. If the metal wire inside is broken or burnt, the fuse is blown and needs to be replaced. 
6. Replace the fuse: If the fuse is blown, replace it with a new one of the same amperage. 

This video explains how to check the brake light fuse and other components: 1mDannys DIY GarageYouTube · Jun 28, 2025

How to tell if a brake light switch is bad?

You can tell a brake light switch is bad by observing symptoms like brake lights that won’t turn on, stay on, or flicker, as well as issues with cruise control, being stuck in park, or ABS warning lights. To diagnose, check for blown fuses, inspect the bulbs, and test the switch’s electrical continuity with a multimeter; if the switch fails the continuity test, it’s likely faulty and needs replacement.
 
Symptoms of a Bad Brake Light Switch

• Brake lights not working: The most obvious sign is that your brake lights don’t illuminate when you press the pedal, even after checking the bulbs and fuses. 
• Brake lights stay on: The brake lights may remain on even when the vehicle is off, indicating a short or a switch stuck in the “on” position. 
• Intermittent or flickering brake lights: The lights might come on and off sporadically due to a loose or unreliable connection within the switch. 
• Cruise control malfunctions: The cruise control might not set, or it could cancel unexpectedly because the switch isn’t sending the correct signal. 
• Stuck in park: The shift interlock system, which prevents you from shifting out of park without pressing the brake, may not release, leaving the gearshift stuck. 
• ABS light on: A faulty brake switch can sometimes disrupt communication with the Anti-lock Braking System (ABS), triggering an illuminated ABS warning light. 

How to Diagnose a Faulty Switch

1. Check bulbs and fuses: Before blaming the switch, ensure the brake light bulbs are good and the relevant fuse hasn’t blown. 
2. Inspect the switch: Locate the switch near the top of the brake pedal and check for any loose connections or physical damage. 
3. Test with a multimeter: Disconnect the electrical connector from the switch. Set your multimeter to continuity mode and test the switch’s terminals. 
   • When the brake pedal is depressed, there should be continuity (a completed circuit). 
   • When the brake pedal is released, there should be no continuity (the circuit should be open). 
4. Check wiring: If the multimeter indicates the switch is faulty, check the wiring harness connected to it for corrosion or loose connections. 

If the switch fails the multimeter test, it’s a strong indicator that it needs to be replaced.