Why is the car brake light always on?
2 Answers
There are two situations when the car brake light stays on: 1. The brake light on the dashboard is on due to: (1) The brake pads are worn to the limit. (2) Insufficient brake fluid. (3) Short circuit in the warning circuit. (4) ABS pump failure. (5) The handbrake is not released or the switch is short-circuited. 2. The rear brake light is on: (1) The brake light switch on the brake pedal is damaged; (2) Short circuit in the brake light circuit. Below is an introduction to brake lights: Brake lights are generally installed at the rear of the vehicle, with the main color being red. They enhance the penetration of the light source, making it easier for vehicles behind to detect the braking of the vehicle ahead even in low visibility conditions, thereby warning the following vehicles and preventing rear-end collisions.
I encountered the same situation last time. The brake light was on all day, and I initially thought it was a minor issue. Later, the battery was almost drained, delaying my work. After checking, the most common cause is a faulty switch under the brake pedal. That thing tends to get stuck and not reset after prolonged use, keeping the light on. You can see a small device under the car. Have a friend press the pedal to test if it moves smoothly. If not, you’ll need to replace the switch—it’s quite cheap, just a few dozen yuan. Don’t underestimate it; if left unchecked, the battery can discharge severely, making it hard to start. I recommend replacing it yourself or consulting a mechanic, and also check for any obstructions around the pedal. Regular maintenance can prevent recurrence.
