[tock172]

BMW's auto leveling system which enables xenon Anti-Dazzle is made up of a small arm on a suspension control arm in addition to the actual adaptive adjustment mechanism on the lights themselves. The purpose of the system, as others have pointed it, is to keep the lights from blinding (or dazzling, as BMW prefers to say) other oncoming driver's. Many new BMWs will also have their headlight angled just a tad lower to keep the direct beam out of the eyes of other traffic.

That being said, the system can and does fail when the small arm on the control arm is disconnected, or the mechanism on the headlights gets brittle and breaks. The repair kit is the typical remedy for the issue if the leveling mechanism on the lights failed, but check all other components first.