My chief mechanic (who has been working on Mini's for years and years) thinks it's a climate sensor. He's sure it's not for lighting, and he's positive it won't change your range.
Speaking of auto-dimming... I thought the Mini has a feature that automatically dims the high beams when an oncoming car approaches or a car traveling in the same direction nears up ahead. I noticed that my high beams didn't dim when an an oncoming car approached. Is it a customizable setting?
Click the lower button on the end of the left stalk, a light icon with an A should appear on the dash
The high beams in the US do not auto-dim, but if you have and use the automatic high beams they do shut off for oncoming traffic. The automatic high beams work very well. Europe gets active matrix headlights that adjust the beam based on what's ahead. Those just became legal in the US with the new infrastructure law, but nobody knows about retrofit possibilities.