01V919821B Auto Transmission Multi-function Neutral Switch For A4 A6 A8 S4 S6 S8 RS6 0501317994 This multi-function neutral switch is designed for installation on automatic transmission systems.It enables proper of the vehicle's starting by the transmission is in neutral or park before allowing engine start.The switch also supports backup light activation when the vehicle is shifted into reverse.Compatible with specified models, it provides feedback for transmission position to the vehicle's control systems.Installation requires proper alignment and connection to existing wiring harnesses.