Diagnostics On Bi-Xenon Headlights
WARNING: This page does not describe the selected car, but rather 37 other vehicles, including the 2006 BMW 330Ci, 2006 BMW 325Ci, 2005 BMW M3, 2005 BMW 330xi, and 2005 BMW 330i. However, it is still accessible from the selected car via links, so may be relevant.
The light switch cluster (LSZ) checks whether or not current flows to the D2-S bulb of the bi-xenon headlights when the dipped beam headlights are switched on. If no current flows, the LSZ detects a fault and stores a fault message.