Haha, maybe I'll buy it I might have a rough idea of what it does. I know there's a light sensor on our R34 dash, on the demister panel on the passenger side. And maybe this auto switch can do what new cars can do nowadays, flick it on auto and your headlights will come on when the sensor thinks there's not enough light? lol
Not sure if I'll need extra bits for it, because I know that if the car didn't come with certain factory option, it will still have the plugs for it, but just hidden away.