How to Deal with the Brake Light Staying On Constantly?
4 Answers
Brake lights are generally installed at the rear of the vehicle. The brake light staying on constantly may be due to a damaged bulb, a short circuit in the wiring, or a faulty brake switch. Damaged Bulb: Brake lights are used most frequently in a car, and the lifespan of the bulb is short. When the brake light does not turn on, the brake light bulb should generally be replaced. Short Circuit in Wiring: The tail lights of a car share a common ground wire. If the ground wire is broken or disconnected, the brake light will not illuminate, so do not forget to check the ground wire. Faulty Brake Switch: If the brake light switch is defective, all brake lights will not turn on. In this case, it is necessary to inspect the switch, and if it is damaged, the brake switch should be replaced. Brake lights are usually installed at the rear of the vehicle, with the main body color being red, serving to alert vehicles behind. Brake lights are categorized by material into gas brake lights and LED brake lights. Gas brake lights have mature technology, with the outer shell made of glass, while LED brake lights use LED materials, which are radiation-free, pollution-free, and have a long service life.
Last time I had my car repaired, I encountered this exact issue—it was a faulty brake light switch. This small black switch is located right above the brake pedal, and pressing the pedal pushes against it. Try reaching in with your finger to feel it; if the switch lacks elasticity or seems stuck, that’s likely the problem. A new switch costs just over ten bucks—unplug the old one and replace it. But if you’re not comfortable doing it yourself, head to a repair shop ASAP—driving without brake lights risks a rear-end collision. Quick tip: On your way to the shop, remember to turn on your hazard lights or have someone follow you to alert drivers behind that your brake lights aren’t working.
Don't rush to dismantle anything yet—first check if the floor mat is jamming the pedal! Many new drivers make this mistake. Last time my cousin drove my car, his super-thick wool floor mat got stuck under the brake pedal, keeping the light on constantly. Nowadays, more advanced cars are quite sensitive—if the pedal doesn’t return to its proper position, the light stays on. Squat down and peek at the gap around the brake pedal, then try pulling it back by hand to see if it springs back. If the spring is broken, it’s an easy fix—just buy a pedal clip replacement on Taobao for no more than 40 yuan. Oh, and when driving to the repair shop, remember to pull out the brake light fuse as a temporary fix—the manual has a diagram showing its location.
Attention to all car modification enthusiasts! If your brake lights stay on constantly, it might be due to a short circuit in the wiring. When I installed cruise control before, the wiring wasn't properly wrapped, causing the brake light wire to rub through its insulation and short circuit. Don't force driving in this condition, as it can burn out the module. Use a multimeter to measure the voltage of the brake light wire; if it shows a constant 12V, the issue lies in the control end. The most troublesome scenario is a fault in the body control module, which requires a visit to the dealership for a computer reset. It's recommended to first disconnect the negative terminal of the battery for three minutes to allow the computer to reboot. Also, for those who have modified their wiring, remember to check the aftermarket installations. There was a case where a fellow car enthusiast burned out the BCM due to incorrect wiring of a streaming rearview mirror.
