A brake light switch is a small device attached to the brake pedal mechanism. Generally, the function of this switch is to illuminate the brake light when the brake pedals are pressed. However, in modern vehicles, this seemingly small switch can do a lot more.
The brake light switch can malfunction and show several symptoms that are both dangerous and annoying. Well, in this reading, we’ll explore what a brake light switch is, its functions, its diagram, and how it works. I will also explain its symptoms, diagnosis, and replacement cost of a bad one.
Let’s begin!
What is a Brake Light Swich?
The brake switch, also known as the brake sensor, is a spring-loaded switch located in the upper part of the brake pedal mechanism.
It is a small device attached to the brake pedal that detects when the brake is applied, closing the brake switch contacts, and signalling the brake to the electronic control unit.
In some vehicles, these switches can be found in two separate forms.
The brake light switch plays a crucial role in modern vehicles. It serves two main functions: turning on brake lights when a driver presses the brake pedal and sending a signal to the vehicle’s computer that brakes are applied.
A faulty brake light switch is unsafe to drive, as it can cause brake lights to not always be on or stay on. In most cars, the brake light switch is installed above the brake pedal with a one- or two-way electric switch.
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Diagram
How Does a Brake Light Switch Work?
The working of a brake light switch is quite simple to understand, as the brake switch is a two-position electric switch that generates a signal when the brake pedal is depressed or not depressed.
It is a simple electric switch with contact terminals and a spring that sends an electrical signal to the circuit.
When the brake pedal is pressed, the spring pushes the contact terminals, making contact. When the pedal is removed, the spring pushes back, causing the contacts to open, cutting off the signal. The brake switch is essential for maintaining proper brake function.
Symptoms Of a Bad Brake Light Switch
If your car’s brake light switch is bad, you’ll notice your brake light won’t display, your car won’t start, the brake lights will stay on continuously, you’ll experience bad cruise control, your ABS warning light will come on, and you won’t be able to move the gear selector. These are some possible symptoms of a bad or failing brake light switch.
1. Your Brake Lights Don’t Light Up
It’s obvious that this is the first sign you’ll notice. When you push the brake pedal, your brake lights should illuminate to alert the driver at your back.
The back brake lights won’t turn on if your brake switch isn’t working properly, which presents a serious safety risk because the vehicle behind you won’t be aware that you’re slowing down.
Now, this can mean that a brake light bulb in the back has burnt out or that your brake light switch is broken.
2. The 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 pushbutton starter, however, could be a problem. 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 models with automatic transmissions may also exhibit this.
3. Brake Lights Stay On Continuously
The brake lights staying on after you turn the car off is one of the most typical signs of a bad brake light switch. This issue is brought on by a short, which causes the system to believe you are still pressing the brake pedal.
This symptom can cause a parasitic drain on your car battery.
4. Bad Cruise Control
If your car has cruise control, a broken or misaligned brake light switch can turn it off. What causes that to occur? The switch for the cruise control and the rear brake lights is frequently shared.
Therefore, if the brake light switch fails, your cruise control will probably too. This does not imply that the brake light switch issue is the only reason the cruise control malfunctions.
A blown fuse in the electronic control module or a malfunctioning speed sensor might also cause it to occur. However, it’s always advisable to take precautionary measures.
5. Gear Selector Can’t Be Moved
One must have your foot on the brake pedal to shift the gear selector out of the park. You may not be able to move the shifter into a different position if the system isn’t understanding your command.
Sadly, this will leave you stuck in your current location. You can resume driving if you can change the switch at the current position.
6. ABS Warning Light Comes On
When the ABS light on your dashboard illuminates, the anti-lock brake system is malfunctioning. When your ABS warning light flashes.
Your car’s ABS module receives information from the brake light switch sensor about when you’ve applied the brakes and when it’s time to activate the ABS hydraulic pump.
Because of this, there’s a potential that your broken brake light switch is to blame if your ABS warning light illuminates.
Problems and Testing of Brake Light Switch
A faulty brake light switch can cause various issues in cars, including the inability to operate brake lights, transmission shifter malfunction, and ABS system warning lights.
In some cases, the switch may be stuck and intermittently work, causing the ABS system warning light to appear on the dashboard. To test the brake light switch, a multimeter can be used without removing the vehicle.
The testing procedure may involve testing the voltage at the brake light switch connector when the brake pedal is depressed and released, or checking the switch continuity with the pedal depressed and released. If the switch does not have voltage, the fuse may be blown.
In some cars, a brake light switch may contain a pair of switches, which must be tested. The correct procedure depends on the car’s service manual.
Replacement Cost of a Brake Light Switch
The brake light switch is a crucial component in cars, and its replacement can be done through a special procedure. The cost of a repair shop can range from $55 to $115, depending on the part and labour.
In some cases, the gap between the brake pedal and the switch must also be adjusted. To ensure proper installation, it is essential to find the correct replacement procedure for your car.
The common way the replacement can be done is by locating the brake light switch, which is often below the brake pedal. You remove the wire and pins, then replace the switch with the new one.
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FAQs
How do I know if my brake light switch is bad?
you’ll notice your brake light won’t display, your car won’t start, the brake lights will stay on continuously, you’ll experience bad cruise control, your ABS warning light will come on, and you won’t be able to move the gear selector.
What is a brake light switch?
The brake switch is a device designed to detect when the brake is applied. When the driver applies the brake, the brake switch contacts are closed, and the electronic control unit is signalled that the brake is applied.
Is there a fuse for a brake light switch?
Yes, in fact you need to check whether or not the brake light fuse has blown. This fuse is usually located in the fuse box under the hood, and it’s easy to check. Just remove the fuse and hold it up to a light; if the wire inside is broken, then you’ll need to replace the fuse.
Is it easy to fix brake light switch?
this is a very easy, stress-free repair. The switch is conveniently located near the brake pedal, making it easy to access. The switch may actually snap into place without the use of any tools at all. $20-50 dollars should cover the labour costs on most cars.
Can I drive with a bad brake light switch?
Yes, your car brake will still work. However, for safety purposes, you are not expected to drive around with it, but at least you should be able to drive to your technician.
