Why does brake light comes on and off while driving & what to do?

When the so-called parking brake is applied, the parking light comes on on the dashboard, but there are times when this light comes on when the vehicle is running. What should we when we see brake light comes on and off while driving.


If the brake warning light comes on as you are driving, you should first stop the vehicle.

1: The parking brake has not been removed

The dashboard parking light is red, therefore action must be taken immediately after it comes on. If the light comes on while your vehicle is running, stop immediately on the shoulder and activate the hazard light. First, you should check that the parking brake is completely removed because otherwise the parking brake switch will be in a closed circuit state and the parking light will come on.

2: There is a defect in the parking brake switch

The parking light may also remain on due to a defect in the parking brake switch or in the parking brake line.

3: The brake fluid level is too low

Most vehicles are equipped with an alarm parking brake warning light for the brake fluid level. The light for this alarm is the same as the parking light. Therefore, if the light comes on and the parking brake is off, we must make sure that the level of the brake fluid is not too low.

Why the brake fluid level drops

If the brake fluid level drops, the alarm light will come on (emergency brake light on while driving), so you need to know what are the main causes of the brake fluid drop.

1: The brake pads are too worn

As the pads wear down with the ride, the brake cylinder pistons gradually extend to fill the gap that remains. Since it is the brake fluid that moves the pistons, when the pistons expand, the space left in the brake pipes grows. This space is filled with brake fluid, causing the level of the fluid reservoir to drop. To solve such problems, the reservoir would need to be refilled or the brake pads replaced.

2: There is a leak of brake fluid

If there is a leak in the brake cylinder and brake pipes, the level of the brake fluid in the reservoir will be too low, in this case, the parking light will also come on. To solve problems of this type, the condition of the leak will be checked and the necessary parts will be repaired or replaced.

If the brake fluid level drops, the alarm light will come on (handbrake light), you need to know what causes this drop.

Remember that the brake fluid reservoir is located in the engine compartment and is marked with two measurement lines: MAX (maximum) and MIN (minimum). It is recommended to change the brake fluid every two years or every 40,000 km. We will check the vehicle maintenance manual to determine the grade of brake fluid to use. It is advisable not to mix several models of brake fluid.

Road House is one of the leading braking brands in the world. Our brake fluids show excellent resistance to both low and high temperatures and great adaptability to both rubber and metal. Our brake fluids are DOT4 compliant, which is why they can be used in vehicles of all classes, including those equipped with a disc brake, drum brake, and ABS system.

Still emergency brake light won’t go off? Read more

If, when you start your car, you unlock the parking brake but brake warning light comes on intermittently, your vehicle may be in trouble. Read what follows, learn what the causes of this malfunction can be, and also how to fix it.

What does it mean when your emergency brake light stays on

1) To rule out that the origin of the failure is caused by a bulb or dashboard lamp, verify that all the lights come on and go off when the internal computer performs routine control when starting the car. If one of the lights stays on when it turns on, there is a fault. If, on the other hand, it never lights, you should change the focus.

2) Press the brake pedal several times, to see if the light turns off.

3) Pull the parking brake lever up to the stop and return it to its original resting place.

4) If, when it is turned off, the light stays on when you carry out steps 2 and 3, the problem is usually less: a small mechanical fault or a simple short fuse.

5) If the light stays on constantly, it controls the level of the brake fluid reservoir, since it is not changed frequently, it is usually not checked regularly. Consult your vehicle manual to locate the tank on the engine.

6) If the tank level is below the minimum, add more liquid.

7) Consult the manual to use the correct type of fluid for your vehicle. When you refill the deposit, do not exceed the maximum level indicated.

8) Periodically check the liquid level, once you have recharged it. If the level drops soon, the system has a loss. Make an urgent consultation with a specialist mechanic and avoid driving with this problem.

9) If the light stays on all the time during winter, the cause could be a brake system cable that does not come loose when you loosen the lever or pedal. There could also be a failure in the device responsible for turning on the lights, which is depressed when you operate it.

10) In winter times, it usually happens that in hydraulic pumps the humidity that absorbs the brake fluid freezes and generates an imbalance in the system pressure. In this case, the solution is to change the brake fluid and bleed the circuit.

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