Car Repair and Maintenance

Bad Brake Light Switch [Symptoms, Diagnosis & Replacement]

Make efforts to have the brake pads replaced if bad and do a system check often to ensure everything is functioning properly. In modern cars, the brake light switch is not just a simple switch that turns on the brake lights. For example, a bad brake light switch can turn on the ABS and traction control lights, but it can also stop the engine from starting or the transmission from shifting.

The aim of this post is to help you identify a damaged brake light switch and replace it to restore the functionality of the brake lights. In this guide, we will examine the most common signs of a malfunctioning brake light switch and go through how to check the brake light switch.

What is a brake light switch?

The electrical switch that turns on the brake lights is known as the brake light switch. The brake light switch makes contact when the foot is depressed, turning on the brake lights. Although brake switch designs might vary, they all function in the same way by turning on the brake lights when the brake pedal is depressed.

The brake lights and the switch that triggers them become intrinsically vital to vehicle safety since they are what warn the drivers behind you that you are slowing the vehicle.

When the brake light switch malfunctions, the car often exhibits a few signs that might notify the driver of the issue.

Brake light switch location?

The brake pedal assembly houses the brake light switch. It can be found either under the firewall or on the dashboard. It is located at the top of the pedal lever. Because it’s so simple to get to, replacing is considerably simpler here.

bad brake light switch location
brake light switch location

Since the 1960s, mechanical brake light switches have been a standard in cars. Automakers had previously used a switch that was activated by the hydraulic pressure present in the lines. This system was terrible and prone to failure.

The brake light switch doesn’t typically break down in current times. Currently, a relay is employed in the design. The main power switch for the car’s brake lights is controlled by the low-voltage circuit. This design allows for dependable switching and a long projected lifespan.

The brake light switch has several functions. Your automatic transmission vehicle’s shifter has to be released from Park. It’s also necessary for push-button start systems to start the engine. The switch analyses the position of the pedal to turn on or off the brake lights at the back of your car.

Symptoms of a bad brake light switch

The following are the symptoms of a bad brake light switch:

1. Brake lights stay on

This is the most common symptom of a bad brake light switch. The brake lights staying on after you turn the car off is one of the signs of a bad brake light switch. The short that was made, which made the system believe you were still pressing on the brake pedal, is what triggers this issue.

Don’t let this situation pass. It causes a parasitic drain on the battery in addition to early wear out of the brake lights.

2. Car won’t start

Using the conventional keyed ignition, a broken brake light switch won’t prevent you from starting the vehicle. Driving a car with a push-button start, though, may get you into trouble.

You might not be able to start the engine because you have to depress the brake pedal. It won’t start if the system doesn’t detect that you are pressing on the pedal. Many car types with automatic transmissions may also exhibit this.

3. Brake lights won’t come on

Another common symptom of a bad brake light switch is that the brake lights won’t come on. On the other hand, a defective brake light switch can result in the failure of the lights. You might still want to inspect this crucial component if it isn’t operating at all.

The lights won’t turn on if the switch doesn’t detect your foot movement on the pedal. When other drivers are unsure of whether you are braking, this creates an on-road risk.

4. Gear selector won’t move

You must have your foot on the brake pedal in order to shift the gear selector out of Park. You might not be able to move the shifter into a different position if the system isn’t understanding your order.

Unfortunately, this situation leaves you stuck in your current location. You can resume driving if you can change the switch at the current position.

5. Illuminated dashboard warning lights

Once you have multiple dashboard warning light, it may be one of the symptoms of a bad brake light switch. Multiple dashboard lights may illuminate when the brake light switch fails since it is a component of numerous systems. The Traction Control or ABS lights are the most frequent indicators.

However, the check engine light can also be seen. This generally only appears when the brake switch is causing you difficulties starting the car. Any lighted light has to be taken carefully and examined straight away.

Brake light switch testing?

The brake light switch is conveniently located, making it simple to diagnose or replace. You won’t need to take it out for diagnostics if you test it with a multimeter.

Reading the service handbook for your car should always be your first step, especially because there are two ways to do the task. While pushing and releasing the pedal, certain cars need you to verify the voltage at the switch connector. Other auto models call for pressing and releasing the pedal while checking the switch’s continuity.

The issue may simply be a blown fuse if the brake light switch isn’t receiving electricity. Fortunately, once you know which fuse has to be replaced, this is a simple fix. Additionally, you could discover that your car has two switches. You must test both of them in this situation. The correct approach should be described in the service handbook.

Brake light switch replacement cost

Spending $75 to $350 on a brake light switch replacement is what is required of you. The parts may set you back $25 to $100, but labor at a reputable shop might cost you $50 to $250. These costs vary based on the type of car you drive and the prices at the nearby shop.

The brake light switch may, however, easily be changed at home, saving you money on labor. Depending on where the switch is, you should only need a few hours to a few days to complete the task.

While the bulk of the switches are placed in convenient locations, certain models have an odd configuration. It can often be impossible to access the switch without removing other parts, which makes the task more challenging.

Bad brake light switch repair process

Replacing a bad brake light switch is an easy job for most handy people and people with some experience, but it can be hard for people who have never done it before. The brake light switch is attached to the top part of the brake pedal, close to where it turns. The brake light switch gets power for the battery from the ignition switch or the Engine Control Unit (ECU). When the brake pedal is pressed, the switch is closed, and current flows to the brake lights through the wiring.

bad brake light switch location
brake light switch location

This turns on the lights for the back brakes. You can also find the brake light switch on the master cylinder. The master cylinder brake light switch system can use hydraulic pressure to close the switch and turn on the brake lights. On a Honda brake light switch, for example, a nut holds the switch in place.

  • First, start by taking the plug apart.
  • Then, take off the nut and turn the brake light switch in the opposite direction of the clock.
  • Turn the switch for the brake lights counterclockwise.
  • This should get rid of the switch for the brake lights.
  • In most GMC cars, a “c” clip holds the brake light switch in place.
  • For safety, unplug the battery.
  • Unplug the brake light switch connector and take off the “c” clip.
  • Watch out that you don’t break the “c” clip.

If the Brake Light indicator is still on, check these things.

  • Change Switch for Brake Lights (if there is room.)
  • Brake Light Fuse Stopper/Bumper Pad for Brake Lights Brake Light Wire Harness

Note that a bad brake light switch can drain your battery if the light stays on and can also shorten the life of your rear brake lights.


A bad brake light switch should never be left unfixed. You will deplete the battery and shorten its lifespan if it is causing the brake lights to remain on. You are placing yourself in danger on the road if the brake lights don’t illuminate at all.

Additionally, if you are unable to use the push-button start mechanism or adjust the gear selector, you risk being stuck.

Once you notice one of the symptoms of your brake light switch going bad, begin the repair process immediately. Otherwise, you may potentially pay more since the problem may extend to something major. Moreover, you may not have to perform brake light switch repairs for the whole time you’d keep the car. But like anything in life, nothing is permanent.


Latest posts by Bernard Juchli (see all)

Bernard Juchli

Bernard Juchli is an experienced racer, mechanic and team owner who trusts Avon Tyres.Bernard is the lead driver and force behind his Big Dog Garage Race Team. He is the General Manager and Chief Mechanic of Jay Leno’s Garage. Bernard and his crew of seven are responsible for all repairs, restoration and fabrication of Jay’s incredible automobile and motorcycle collection.

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