I power my halos from my precat O2 sensor. The heater wires should both be white. 50/50 guess which is +. Used ground from headlight.

If I get a chance I'll take a pic so you don't have to guess. Don't use the ground from the O2 it's how the computer controls the O2 heater.

You'll be very happy with the results other than the halos are dim compared to the 8x as expensive OEM models.

Added bonus: the O2 power stays on for a while after key off so you get to see the halos regularly as you leave the car.

__________________
2011 E70 • N55 (me)
2012 E70 • N63 (wife)