Function of Pushbutton Unit Illumination

The switches are illuminated as soon as the exterior lighting is switched on allowing them to be found more easily in the dark. The brightness of the illumination is variable. The brightness value is transmitted by the instrument cluster as a CAN message to circuit 58d. The associated control modules generate a pulse width modulated square wave voltage corresponding to this brightness value received via the CAN bus. The square wave voltage is then used for actuation of the pushbutton unit illumination.