Mercedes light A fog light is a type of automotive light designed to provide improved visibility during foggy, rainy, or snowy conditions. Unlike regular headlights, which are angled to illuminate the road ahead, fog lights are mounted lower on the vehicle (typically near the bumper) and are designed to cast a wide, low beam of light. This unique beam pattern helps illuminate the road immediately in front of the car, reducing the glare and reflection off the fog or precipitation,