Webasto Motherson Sunroofs Limited offers Automatic Rain Sensor for Car Roof. Webasto Motherson Sunroofs Limited supplies sun roof, slide and tilting roof, parking ventilation with solar system etc. For application in automobiles. The Automatic Rain Sensor for Car Roof allows the car roof to be slightly opened for ventilation on a hot summer`s day and when it starts raining, the rain sensor reacts immediately by automatically closing the sunroof.