Rain And Light Sensor (RLS)
The rain/light sensor is integrated in the rear-view mirror pedestal attached to the windshield. The RLS is a combined rain sensor and ambient light sensor. It detects the amount of rain falling on the windshield in order to control the windshield wipers, and the level of ambient light in order to control the headlights.
The rain sensor sends the "Switch on wipers" request to the body basic module (KBM) via the body CAN-Bus (K-CAN).
If the rain and light sensor should fail or be faulty, the KBM will take control. The KBM will switch to an emergency mode. Emergency mode is a speed-dependent intermittent mode.