The Genuine BMW Auxiliary Fan Switch - 61318360857 is a replacement part for the auxiliary fan in BMW vehicles. This switch is responsible for regulating the operation of the auxiliary fan, which helps to cool the engine and prevent overheating. It is a genuine OEM (original equipment manufacturer) part, ensuring high quality and compatibility with BMW vehicles. This switch is designed to meet the same specifications and standards as the original part, making it a reliable and durable replacement option.