Why is the yellow light on the Passat's rearview mirror on?

[Marcus]

If the yellow lights on both side mirrors are flashing, it indicates that there is a vehicle approaching from the side or rear. Introduction to Blind Spot Detection Function: The flashing yellow light on the side mirror is part of the vehicle's blind spot monitoring system. When there is a moving obstacle approaching or moving away from the side or rear of the vehicle, this light will illuminate to alert the driver of the presence of a vehicle or pedestrian in the blind spot. This helps the driver to be cautious when changing lanes or turning, thereby avoiding traffic accidents caused by blind spots. Purpose of Blind Spot Detection: Blind spot monitoring uses microwave radar to detect overtaking vehicles in the blind spots on both sides of the vehicle and alerts the driver. This helps prevent accidents that may occur during lane changes due to blind spots in the rearview mirrors.