Recently, a similar thread in the THub was closed:
Explanation: “We are closing this topic as “Won’t Fix” for technical reasons: car headlights are aligned to game-world timing and cannot react to brightness”.
Okay, they cannot react to environmental brightness (which makes sense) but they surely could react to a keybind, i.e. be activated manually? 
The same goes for wipers.
These features are a must-have for a title that’s meant to be considered a sim 