The headlights use Infrared (IR) light sensor to detect when to turn on. Like when its bright but foggy out, they will switch on. Also IF you use your wipers... they will also switch on.
IF you look closely at the headlight switch... when the headlights are on there is a tiny green led lamp. When the green led is on, the headlights are on.
Someone posted a long time ago that the Infrared (IR) light sensors are built into the headlights. Another reason why the headlights cost so much!
IF you hack the instrument panel cluster there is a way to adjust WHEN the headlights switch on. I also believe there is an adjustment menu when using a BavTech (BT) scan tool in one of the menus. Or your dealer can also adjust when the lights witch on.
My headlights turn on just fine. They are almost perfect when in the auto mode. EVery once in a while I will have to turn them on manually... but for the most part they know AND turn on when I need them.
