Rain/light sensor
WARNING: This page does not describe the selected car, but rather 7 other vehicles, including the 2017 BMW X3, 2016 BMW X3, 2015 BMW X3, 2014 BMW X3, and 2013 BMW X3. However, it is still accessible from the selected car via links, so may be relevant.
The rain/light sensor is also an optical sensor and consists of two photo diodes and the corresponding electronic evaluation unit. A photosensor that works in the infrared range is aligned forwards and it picks up the light that strikes the front (frontal light). A second diode; which works mainly in the visible light spectrum, is aligned upwards and picks up the light striking from above (ambient brightness).
Vehicles with head-up display (HUD):
With models up to 09/2008, a modified rain/light sensor adjusts the brightness of the Head-Up Display.
With models from 09/2008 onwards, a separate photosensor in the rain/light sensor adjusts the brightness of the Head-Up Display.