The brake lights on a car do not light when the brake pedal is depressed. What is the least likely cause of this issue?

The least likely cause of the brake lights not illuminating when the brake pedal is depressed is a burned-out bulb. While it is possible for a bulb to burn out and therefore not function, this scenario typically affects one light at a time rather than the entire brake light system. Moreover, in many modern vehicles, the brake lights have multiple bulbs, meaning that even if one were burnt out, the others could still operate, leading to at least partial illumination.

In contrast, a faulty brake switch or a blown fuse can directly prevent the electrical circuit from completing, which results in all brake lights not functioning when the pedal is pressed. Worn brake pads, while they can impact braking performance, do not interact with the brake light system and would not cause the lights to fail to operate, making their influence on this specific symptom negligible. Thus, the burned-out bulb is the least likely cause when considering a complete failure of the brake lights.