The choice is yours. The 2 wires running from the LED unit, one gives you an orange halo the other is a white halo. Yellow and black wires. As the standard headlamp is already earthed by the main bulb the black is not needed. The yellow is the power of the Halo. This is the one you want to connect to whichever Halo color you require. If you use the wrong wire the Halo up will not work.