So by setting this setting all the way to the right, do the lights come on when there is more or less ambient light present? On a recent cloudy day, I turned the lights on to auto, but the lights didn't come on. Had to turn the switch all the way to have them turn on.

Maybe it would be been better to have the auto position as the last position on the switch rather than the first.

 

If you set the sensitivity all the way to the right, the lights will turn on with less ambient light hitting te sensor. You will notice wen going under bridges the lights will turn on and then off when you clear the bridge. I have mine set one notch from full right and it works well that way. I had it all the way and it was annoying how they would turn rapidly on an off the second the sensor sensed a shaded area. Like someone asked earlier, it's not good for the HID's to turn on and off in less than ten seconds because the lights are still warming up, and that could lead to premature HID failure.