Why don't the brake lights come on when the headlights are on?

[KateRose]

There are several reasons why the brake lights may not come on when the headlights are on: Brake light bulb failure: The most likely cause is a burnt-out brake light bulb, as these bulbs are used frequently. The owner can replace the brake light bulb with a new one. Alternatively, check for poor contact and adjust the bulb if necessary. Brake light switch: The owner can also check if the brake light switch is faulty, causing the brake lights not to work. By connecting the brake light switch with a wire, if the bulb lights up, it indicates the switch is damaged, and the owner can replace the brake light switch. Blown fuse: A blown fuse can also cause the brake lights not to work. However, some cars do not have a separate fuse for the brake lights but share it with other electrical devices. The owner can check for non-functioning electrical devices in the vehicle and replace the corresponding fuse.