Non-Networked Illumination Operation
WARNING: This page is about a different car, the 2013 Ford Fusion. However, it is still accessible from the selected car via links, so may be relevant.
Based on the ambient light level input from the autolamp/sunload sensor and the requested illumination dimming level input from the dimmer switch, the BCM calculates the correct dimming level for the hardwired illumination sources. The BCM provides a pulse-width modulated voltage to all hardwired illumination sources on 1 circuit.