Brake Light Switch (Fuctions, Symptoms & Replacement)

Why do cars have brake light switches? How do you know when it is faulty, and how do you repair it? These are questions that get you curious, and you earnestly want an explanation.

The basic information you need and even more is contained in this article. You would want to take a look!

The purpose of the article is to give a detailed explanation of everything related to brake light switches, such as why they are installed in cars, the importance of having one, and how it can be fixed when it malfunctions.

Furthermore, there are guidelines provided in this article that guarantees the proper functioning of your brake light switch. 

Read on to find out more! 

What Does A Brake Light Switch do?

A driver behind you might not notice you are slowing down when you hit on your car brakes. This is where a brake light switch comes into the picture. A brake light switch is an electrical device found above the brake pedal that activates brake lights when car brakes are stepped on. It is usually small and has either a one-way or two-way electrical switch.

It serves a significant purpose. When the brake light is switched on due to you activating the brake light switch, the driver behind you or in front of you gets an idea that you are slowing down or stopping your vehicle.

Vehicle’s Brake light switch, ABS, Cruise Control system, Push-Button Start, and other such systems all function together. If there is a fault in the Brake Light Switch, it affects the system.

The two main functions of Brake Light Switch include:

  1. It acts as an activator when the brake pedal is stepped on.
  2. It signals the vehicle’s computer when the brakes have been activated.

A Brake Light can not function without a switch. You should get your brake light switch repaired before driving again if it is faulty.

Also Read: What is a Serpentine Belt & When Should You Replace It

Symptoms Of A Bad Brake Light Switch?

Usage promotes damages. These symptoms indicate a bad Brake Light Switch that needs repair or replacement.

1. Your Brake Lights Do Not Come On

Your brake lights should turn on when your foot touches the pedal. This is to signal the driver in front of you that you are using the brakes.

A malfunctioning brake switch can cause the rear brake lights to not illuminate, and the driver in front of you will not know you are slowing down. This is a serious safety risk.

This could be a sign that your rear brake light bulb has burned out or that your brake light switch is defective. To quickly identify the problem, you might consider having a mechanic inspect your vehicle.

2. Brake Lights Are Always On

If you find out that your brake light switch is always on, A short circuit in the electrical circuit of the rear brake light switch can cause this problem. If the brake lights are always on, it won’t serve its purpose.

A driver behind you might not notice you are slowing down when you hit on your car brakes. In addition, if the brake lights are always on, your car battery drains quickly, and the bulb burns out faster. Get your brake light switch fixed immediately if you encounter this symptom.

3. Bad Cruise Control

The vehicle’s Brake light switch and Cruise Control system work hand in hand. Each of them can’t function without the other. This is because the cruise control system and rear brake light switches share the same switch most times.

Nevertheless, your cruise control system will still be able to function even if your brake light switch is bad.

This can also occur due to a damaged speed sensor or a blown-up fuse in the electronic control module.

Inspect any problem in the brake light switch if your cruise control system stops working.

4. Car Won’t Start

Cars without a key ignition system can only start by hitting the brake pedals. In this situation, you need a good brake light switch that would signal the vehicle’s computer that the brake has been activated. If your car doesn’t start, it might be because of a bad brake light switch.

If this happens, contact a mechanic or car repair shop immediately to replace your brake light switch.

5. ABS Warning Light On

A bad brake light switch or faulty Anti-lock brake system can make an ABS warning light power up. Other Faults that can cause this include Low brake fluid, Faulty ABS Control Module, and many more.

Just like the brake light switch signals the vehicle’s computer that the brake has been activated, the ABS module signals the vehicle’s computer that the ABS hydraulic pump is working properly.

How To Test Brake Light Switch?

How To Test Brake Light Switch
Credits: Mark Nazh / Shutterstock

You cannot determine a bad brake light switch by simply pressing the brake pedal and checking the lights. This test could be misleading.

Although the brake lights may be working properly, it is possible that the brake light switch might still be defective and require replacement. 

Here is a step by step method to test your vehicles brake light switch

Make use of a multimeter, set in ohms. Both the positive and negative sides must be tapped on one pin.

There should be a continuity reading below zero. The brake light switch has failed if the reading is more than zero.

  • Assume that the brake lights have no fault.
  • Test for brake light switch power.
  • Locate the wire connector connecting the brake light switch.
  • Locate the power source with a voltmeter.

A brake pedal stopper can also cause a brake light to remain on. If the brake pedal stopper is not pressed, direct contact with the brake light switch is allowed.

Even if the stopper wears out over time, it will not prevent the light switch from functioning.

Adjust the brake light switch when you want to check this problem. When adjusting, press the brake light switch against the brake stopper and replace it if the brake light stopper gets damaged.

Brake Light Switch Replacement Cost?

Brake light switch replacement costs between $30-$100, depending on your car’s make and model and depending on the difficulty and shop rate. On Average, Brake light switch replacement cost $80

It may be necessary to remove several components to access the brake light switch in some vehicles, and removing several components can increase the repair cost. 

If your brake switch fails, you should replace it as soon as possible. A bad brake light switch could drain your battery since it causes the brake lights to stay on. It can also reduce the life expectancy of your rear brake lights.

How To Replace Brake Light Switch

Watch this video to know How to replace a Brake Light Switch

Frequently Asked Questions

What will a bad brake light switch cause?

Bad brake light switches can lead to many problems. Bad switches can cause brake lights to stop working and the transmission shifter to not move from the “Park” position. A faulty brake light switch in cars that have a push-button ignition system can cause the vehicle to not start.

How long does it take to replace a brake light switch?

The process takes just an hour, and you can save nearly $200 if you use an aftermarket replacement motor. For replacement motors, check with an auto parts dealer online or at a local shop.

How often should you replace the brake light switch?

Brake light switches will last longer than brake pads and are therefore expected to last twice as long as your vehicle. It is possible for your brake switch’s internal components to wear over time, particularly if you have a mechanical brake light switch that uses a plunger style.
It is important to maintain the safety of your brake lights by checking their condition. You may also need to replace your vehicle’s push-button ignition switch if it doesn’t turn on.

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