Why do the brake lights stay on without pressing the brake pedal?
3 Answers
This situation is generally caused by the brake light switch not returning to its original position or internal rust leading to poor contact. Here are the relevant explanations: Brake lights: Brake lights are usually installed at the rear of the vehicle, with the main color being red. This enhances the light's penetration, making it easier for vehicles behind to notice when the front vehicle is braking, even under low visibility conditions, thereby helping to prevent rear-end collisions. Reasons why brake lights may not work: Bulb damage; short circuit in the wiring, as car tail lights share a common ground wire. If the ground wire is broken or disconnected, the brake lights will not illuminate, so don't forget to check the ground wire; brake switch damage, if the brake light switch is faulty, all brake lights will not light up, in which case it's necessary to inspect and replace any damaged parts.
I've encountered several instances where the brake lights stayed on without pressing the pedal, which is mostly caused by a faulty brake light switch. Those old-style switches can get stuck internally after prolonged use, keeping the circuit energized—no wonder the lights stay on. Wiring issues could also be to blame, like frayed insulation under the steering wheel causing a short to ground. When checking yourself, first verify the fuse box is intact, then inspect the trunk light socket for water damage or rust. Another common culprit is aftermarket electronics like reverse radar systems interfering with signals. If you notice this issue, address it immediately—don't try to live with it. Driving at night with trailing cars aggressively flashing high beams at you is unbearable.
I've had this issue when fixing my own little old car, usually it's the small switch inside the brake light switch not returning to position. Every time you press the brake, it makes that squeaking sound, and over time the spring loosens or the push rod bends, causing it to stay stuck and keep the circuit closed. Also, things like water getting into the wiring connectors causing rust or a loose ground wire can lead to a short circuit. I suggest opening the hood after parking and feeling if the switch area is hot—if it's warm, that means it's secretly working. Replacing the switch yourself isn't hard; you can buy an original part online for just a few dozen bucks, just make sure you don't get the wrong model to avoid wasted effort.
