the harness connects straight to your battery with an in line fuse not from you oem harness well only one side connects to you oem plug to gain control from your switch the balast connect to the bulb and to a relay and the harness has ground wired for each one. it draws power straight fro your batter making you bulbs brighter and last longer. so if anything goes wrong the will go first instead of your hid componets.
for your fog light i would reccomend this harness Car HID Xenon Conversion Harness Fuse Relay Wire For H8/H9/H10/H11/880/881 | eBay
this is the one i got and its made pretty well good connections and evreything is heat shrinked.
the only thing you might have to do is you might have to lengthen the battery wire because it is a little short
