5 symptoms of a bad brake light switch (and replacement cost)


Having properly functioning brakes is vital in any vehicle. Do your best to have your brake pads changed and perform a system check from time to time to make sure everything is working properly. However, you have no control over the switches and sensors in the system, leaving people wondering about the symptoms of a bad brake light switch.

The brake pedal switch is part of the pedal assembly, alerting the lights to come on when you need to slow or stop the vehicle. When it is faulty, it leads to car starting problems, malfunctions with the brake lights, trouble shifting the gear selector and illuminated dashboard lights.

That said, you can diagnose a bad brake light switch and replace it to get the brake lights to work once again. In this guide, we will look at the main symptoms of this failing part and discuss how to test the brake light switch.

Symptoms of faulty brake light switch

1. The car does not start

Start the car

In traditional key ignition, having a bad brake light switch will not affect the ability to start the car. However, if you drive a vehicle with a start button, you could be in trouble.

Since the brake pedal must be depressed to start the engine, it may not be possible to get it to work. If the system does not recognize that you are pressing on the pedal, it will not start.

This can also be true in many models of automatic transmission cars.

RELATED: Does the car not start? (10 reasons and how to fix it)

2. Brake lights stay on

One of the most common symptoms of a faulty brake light switch is when the brake lights remain on even after the vehicle is turned off.This malfunction is caused by the short circuit created which leads the system to think that you are still pressing the brake pedal .

You will never want to let go of this situation. Not only will it wear out brake lights prematurely, but it will also lead to parasitic battery drain.

RELATED: Do the brake lights stay on? (5 causes and how to fix it)

3. Brake lights do not come on

On the other hand, a bad brake light switch can cause the lights to fail. If it doesn’t work at all, you may still want to check out this vital part.

If the switch doesn’t read your movement on the pedal, the lights won’t turn on. This poses a road hazard when other drivers don’t know if you are braking.

4. The gear selector cannot be moved

To move the gear selector out of Park, you need to keep your foot on the brake pedal. If the system does not read your command, you may not be able to move the shifter to another position.

Unfortunately, this circumstance leaves you stuck where you are. If you can replace the switch where you are, you can go back to the street.

5. Dashboard warning lights

Since the brake light switch is part of several systems, multiple dashboard lights can come on in the event of a malfunction. The most common lights are ABS or Traction control.

However, it is also possible to see the Check the engine light. It will normally only come on if you are having trouble starting the vehicle due to the brake switch. Any lights on should be taken seriously and checked immediately.

Brake light switch position

Brake light switch position

The brake light switch is located inside the brake pedal assembly. You will find it under the firewall or dashboard. It is located at the top of the pedal lever. This location is easy to access, making replacement much easier.

The mechanical brake light switch has been used in vehicles since the 1960s. Previously, car manufacturers relied on a switch operated by the hydraulic pressure present in the lines. This system was a disaster and could easily fail.

In modern times, the brake light switch usually does not fail. With the current design, a relay is used. The low voltage circuit operates the main power switch for the car’s brake lights. With this design, reliable switching occurs and a long service life can be expected.

The brake light switch has many jobs. It is required to release yours automatic transmission change of vehicle outside the parking lot. In push-button start systems, it is also required to start the engine. The switch reads the pedal position to illuminate or turn off the brake lights at the rear of the vehicle.

How to test a faulty brake light switch

Brake light switch

Due to the convenient location of the brake light switch, it is not difficult to diagnose or replace. You can use a multimeter to test it and you won’t need to remove it for diagnostics.

You should always start by reading your vehicle’s service manual, especially since the procedure can be done in two different ways. Some vehicles require checking the voltage on the switch connector while pressing and releasing the pedal. Other car models require testing the continuity of the switch while depressing the pedal and releasing it.

If you don’t get voltage at the brake light switch, the problem may just be a blown fuse. Thankfully, this is an easy fix once you understand which fuse to replace.

You may also find that your car contains a pair of switches. In this case, you will need to test them both. The service manual should outline the correct procedure.

Cost of replacing the brake light switch

To replace a brake light switch, you can spend between $ 75 and $ 350. Parts could cost $ 25 to $ 100, while work in a professional shop could range from $ 50 to $ 250. These prices vary depending on the type of vehicle you drive and the rates at the local shop.

However, it is not difficult to replace the brake light switch at home, thus saving money on the job. In total, it should only take five minutes to a couple of hours, depending on the switch position.

While most switches are located in easy-to-access locations, there are some models that have an odd configuration. There are times when it may be necessary to remove other components just to access the switch, making it more difficult to complete the job.

That said, you should never leave a faulty brake light switch unrepaired. If it causes the brake lights to stay on, you will drain the battery and reduce its life. If the brake lights don’t come on at all, you are putting yourself in danger on the road. Also, you may get stuck if you can’t move the gear selector or use the push button start system.

For the low price associated with this repair, it makes sense to only perform it at the first sign of problems. Considering that the switch is expected to last for the life of the vehicle, it is unlikely that you will have to perform the same service again.


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