Mercedes Vito W447 Electronic Ignition Switch EIS EZS Repair Service.Mercedes Vito V class W447 Electronic Ignition Switch EIS EZS Repair Service. Many Mercedes Benz vehicles are fitted with Electronic Ignition Switch EIS EZS. The Electronic Ignition System (EIS) breaks or malfunctions, which is typical for this component. However, when this unit does fail, it can pose a significant problem for customers, often necessitating the expensive replacement of the EIS if they visit the main dealer. Instead of replacing it