I have read that you have to file a tab down to on the HID harness to put it on an ls that came with halogen headlights, but i have never seen or known which tab it is. I have HID headlight but I bought them from someone who swaped them out for his halogens so he had already modded them to fit. I had a pair of HID headlight that came on LS and I was able to see the difference in them. A pic of the tab that you file down, for those in the future that want to do the swap.