The brake light bulbs are located at the rear of the car, Inside a protective lens. The brake light comes on when you press the brake pedal, indicating the other road users that vehicle is slowing down. Keep in mind that the number of brake lights on a car can vary. The third brake light (center high mounted) should not be overlooked during an inspection.
Due to the large amount of current flowing through the plugs, the plugs sometimes melt, causing the brake light to malfunction. So its very important to check the condition of the plugs when replacing the bulbs.
When you apply the brakes, the brake light bulb comes on. This allows the drivers behind you to understand that you are slowing down, so they can slow down as well. If brake light bulb does not work, your safety would be compromised. Not having working brake lights is also illegal and can result in a substantial fine.