How It Works
WARNING: This page is about a different car, the 2005 BMW 645Ci and 2004 BMW 645Ci. However, it is still accessible from the selected car via links, so may be relevant.
The signals used to generate the image in the head-up display are input from the corresponding control units, e.g. multi-audio system controller (M-ASK) via the K-CAN and MOST data buses to the electronic circuitry in the head-up display. The electronic circuitry evaluates the incoming signals and forwards the prepared image information to the components in the head-up display.