Blog Car Care Advice 6 Reasons the Brake Light on Your Dash Is On (+ How to Fix It)
Car Care Advice

6 Reasons the Brake Light on Your Dash Is On (+ How to Fix It)

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Is the brake warning light on your dash illuminated?
Well, it could be due to problems within your braking system, like worn brake pads, fluid leaks, and more. 

So what should you do when the light comes on? 

Keep reading to explore everything about dashboard brake lights, from the reasons they come on to the steps you can take to resolve these issues. 

This Article Contains:

What Does a Brake Light Warning on Your Dash Mean?

An illuminated brake light warning on your vehicle’s dashboard (usually red in color) is a sign that something’s wrong with your braking system. This red brake warning light may appear as an exclamation point (“!”) inside of a circle or simply as a message that spells out the word “BRAKE.”

Besides this, many other brake-related lights on your dashboard can illuminate in response to different problems with the brake system. 
Here’s how they may appear:

So, what causes these different brake lights to come on?
Find out next.

6 Reasons Your Dashboard Brake Light Is On

The brake warning light could be triggered by bad wiring, a faulty brake sensor, or a blown LED bulb.  
Here are the six most common culprits why your dashboard light is on:

1. An Engaged Parking Brake

This is the most common reason why your brake light is on. 

If the parking brake (emergency brake or hand brake) is engaged, the parking brake sensor prompts the brake warning light to illuminate. This usually happens when you don’t fully release the hand brake, and the solution is to disengage it completely.

If you leave it as it is, you’ll be driving around with activated parking brakes. Doing so will overheat your brakes, accelerate brake shoe or brake pad wear, and cause a brake lockup.

The increased temperatures can also speed up hydraulic fluid degradation and reduce the efficiency of your braking system.

2. Low Brake Fluid Levels

A sensor in the brake master cylinder monitors the brake fluid level in the system. If the fluid levels are below the minimum threshold, the sensor will trigger the brake light to illuminate.

You shouldn’t take a low brake fluid level lightly, as it might indicate a fluid leak in the brake line, which will need addressing ASAP.

3. Worn Brake Pad

A worn brake pad can lead to a drop in brake fluid level as the caliper pistons have to reach further to contact the rotor, triggering your brake warning light. 

In some cars, once the brake pads are too worn, a brake pad sensor wire contacts the rotor and forces the brake light (or brake pad warning light) to light up.

Note: Worn brake pads can also produce a noticeable squealing or grinding brake noise, which is an early indicator of brake pad wear. 

4. ABS Malfunction

Most vehicles with an anti lock brake system (ABS) have an ABS warning light. 

ABS system problems can trigger the brake light and ABS warning light (if it has one) to turn on. The causes can range from an electrical malfunction to something as simple as a dirty wheel speed sensor. 

When this happens, have an auto professional review your ABS codes to determine the issue.

5. Defective Sensors

Throughout your vehicle, there are many sensors linked to the brake system. This includes the hand brake sensor, master cylinder sensor, ABS sensor, and brake pad sensor. If any of these sensors malfunction, they could trigger your dash brake light to turn on.

6. Faulty Rear Brake Light Bulb

Some car computers monitor the rear brake light bulb, which could be a single red light bulb or even an LED bulb array.

If a brake bulb goes out or dims, it may cause the brake warning light to turn on. This helps prevent rear-end collisions since drivers don’t often realize their rear brake lights aren’t working.

While you can swap the rear brake light bulb yourself, getting a mechanic to do it is better, as each motor vehicle may have a different light bulb type and varying bulb socket access.

Now that you know the causes, let’s see what you can do when the brake light comes on.

What Should You Do if the Dashboard Brake Light Comes On?

Here’s how you can deal with an illuminated brake warning light in five different situations:

1. The Dashboard Brake Light Turns on Before You Drive

If you haven’t begun driving, check your handbrake and ensure it’s completely released. 

If the brake light stays on even after you release the parking brake, you can check the brake fluid level and consider topping it off if it’s low. It’s best to get your mechanic to do this because your brakes may need to be bled of air

2. The Dashboard Brake Light Turns on While You’re Driving

If you’re driving and the dash brake light comes on, pay attention to your brake pedal. If there’s a brake fluid leak in your car’s brake system, your pedal may feel different. You can always stop at the first safe spot you find and then check the brake fluid level.

If it’s an emergency and your vehicle has a low brake fluid level, you can top it off (if you have fresh brake fluid). However, getting your vehicle to a trusted mechanic for a brake checkup is still important.

3. The Dashboard Brake Light Is Always On

If the parking brake is disengaged but the light remains on, it could indicate problems like worn brake pads, hydraulic brake pressure issues, or a need for parking brake adjustment. 

You should visit a mechanic for prompt replacement and adjustment, as neglecting these issues can compromise your safety and lead to your vehicle producing a weird brake noise.

4. The Dashboard Brake Light Turns on When You Press the Pedal 

If your brake light illuminates only when you press the brake pedal, it may indicate hydraulic loss on one side of your vehicle or low brake fluid in the brake master cylinder. This can lead to a complete loss of braking ability, putting you and other drivers on the road in danger.

When this happens, you should gradually reduce your speed and find a safe place to pull over. You can either call a mobile mechanic for a system inspection and brake repair or get your car towed.

5. The ABS Light Comes On and Stays Lit 

When you start your engine, the ABS light should briefly flash for a few seconds and then turn off, indicating a regular operation. However, if the ABS light stays on, it suggests a problem with your ABS, which is designed to prevent skidding and brake lockup.

While you can still drive with the ABS warning light on, it’s advisable to take your vehicle to a repair shop and get it checked.

Got more questions?
Let’s explore some FAQs.

6 Brake Light FAQs

Here are answers to some commonly asked questions about brake lights:

1. How Do Brakes Work?

When you depress the brake pedal, the brake booster amplifies the force from your foot. This force is converted into hydraulic pressure by the master cylinder. This hydraulic brake pressure is then transmitted through the brake fluid (in the brake line), engaging the brake mechanisms. 

The exact braking mechanism can vary based on your car.

It could either be brake calipers that clamp the brake pads onto the rotor or brake disc (in disc brakes) or wheel cylinders that push the brake shoe against the brake drums (in drum brakes). 

2. How Do I Verify if the Brake Warning Light Is Working?

When you turn on the vehicle ignition (but before you start the engine), each dash light should illuminate for a few seconds. 

This is designed to help you verify that each warning light and its corresponding system is operational before you start your journey. If some don’t illuminate, it means there’s likely a problem — like a blown fuse or a worn-out light bulb.

3. How Can I Check the Brake Fluid Level if the Brake Light Is On?

Your best option is to leave this task to a mechanic. However, if it’s an emergency, you can do it yourself — carefully by taking the following steps:

  1. Ensure that your car is in a secure and level location before you pop the hood to check the brake fluid level.
  1. Locate the brake fluid reservoir — usually found on the same side as the brake pedal, at the back of the engine compartment near the firewall. 
  1. If the brake fluid reservoir is translucent, check the fluid level against a clearly labeled “FULL” (or “MAX”) line without removing the reservoir cap. However, if it’s not translucent, pop the cap and check the fluid level inside the reservoir.

Note: Never leave the brake fluid reservoir open any longer than necessary, as moisture in the air can contaminate the brake fluid. 

4. How Can I Check if the Rear Brake Lights Are Working?

Reverse your vehicle close to a wall and press the brakes. If your rear brake lights work fine, you should see a red glow on the wall. If there’s no glow, you might have a problem with the brake light switch, a faulty bulb, or a blown fuse.

It’s also a good idea to ensure that all your car lights (including the headlight, tail light, turn signals, and fog light) are working while you’re at it. 

To do this: 

  1. Activate the light switches for the headlight, rear tail light, and fog light. 
  2. Put the headlights in parking or auto light mode to see if your daytime running light works.
  3. Press the brake pedal to activate the brake light switch and the rear brake lights.
  4. Switch on the hazard light to flash the turn signal lights. 

If there’s a problem with either of these, get them fixed ASAP, as they can affect your road safety.

5. How Is the Rear Brake Light Bulb Changed?

Some vehicles have different light bulbs for the turn signal and the brake light (rear light). 
Others may have a single light bulb with two filaments inside — doubling as the turn signal bulb and rear brake light bulb. 

Since the replacement can be cumbersome, it’s best to let a professional handle it.
Here’s how a mechanic would change the bulb:

  1. Get the correct replacement bulb for your car or truck. 
  2. Remove the tail light assembly to access the bulb socket.
  3. Smear some dielectric grease to the end of the new brake bulb before installing it to prevent corrosion.  
  4. Install the replacement bulb. 
  5. Reattach the tail light assembly.

6. How Much Does it Cost to Fix Brake Light Warning Issues?

Fixing brake light warning issues can vary depending on the problem and your vehicle’s make and model. You can expect to pay around $80 – $110 for a basic brake system inspection, but repair prices may vary based on labor rates in your area.

Here are the estimated costs for addressing some brake light warning issues:

Get Rid of Brake Light Issues with AutoNation Mobile Service

The red brake warning light on your dash can indicate various issues, from ABS malfunction to worn brake pads. And driving with such braking system issues is never a good idea. 

Why not have a trusted mechanic come to you to address those brake issues?
That’s where AutoNation Mobile Service steps in. 

We’re a mobile auto repair service available seven days a week, offering upfront pricing, easy online bookings, and a 12-month, 12,000-mile repair warranty. 

Contact us, and our skilled mobile mechanics will carry out all brake system replacements and repairs in your driveway.