What Causes the Car Brake Light to Stay On?
2 Answers
If the brake light remains illuminated, potential faults can be identified as insufficient brake fluid, a faulty brake switch, or worn-out brake pads. Insufficient Brake Fluid: Brake fluid plays a crucial role in the car's braking system. When the driver presses the brake pedal, the force applied is transmitted by the master cylinder piston through the brake fluid to the wheel cylinders at each wheel, causing the brake pads to contact the wheels and stop the vehicle. Insufficient brake fluid may also be accompanied by noticeably reduced braking power, and in severe cases, a complete loss of braking force. This issue can be resolved by promptly replenishing the brake fluid. Faulty Brake Switch: This usually occurs when the brake pedal does not properly contact the brake sensor switch or the sensor switch itself is damaged, requiring disassembly for inspection. Worn-out Brake Pads: Worn or aged brake pads can also cause the brake light to stay on. In this case, it is necessary to check the thickness of the brake pads. If the thickness is below the specified value, typically 0.8cm, there is a high risk of the pads cracking during driving, which could be dangerous.
When the car's brake lights stay on continuously, the most common issue is a malfunctioning brake light switch. This switch is usually installed behind the brake pedal. If it's worn out, improperly adjusted, or the contacts are stuck, it can keep the circuit closed, causing the lights to stay illuminated. Another possible cause is a short circuit in the wiring, where aged or damaged wires allow continuous current flow. I suggest first checking the switch position—use your fingers to feel if there's any looseness under the pedal. Then, use a voltmeter to test the current. If there's a short circuit, avoid tampering with the wires yourself as it may blow fuses or drain the battery quickly, making nighttime driving particularly hazardous. It's best to drive straight to a repair shop for professional assistance. Regular maintenance, such as cleaning the pedal area, can help prevent this issue and keep the system responsive for safety.