Its most likely a marker light to meet a requirement in a different region.. I know its not functional in my U.S. car without hids.. I bet you could wire it up as a DRL or a Marker light..
I thought the sensor for the auto on is on the dash? I will check mine today and see.
From what I see on here it is on the dashThere is no sensor on the dash. The only thing that is up there, is a little square section with a red led in the center that flashes when the security system is armed. My Sportage on the other hand, does have a sensor on the dash.