Micro Fuse Tap harnesses are used to source ignition-switched power via the fuse block of the vehicle with little to no modification. To install: determine which 10A fuse is switched on/off as desired. Remove existing 10A Micro fuse. Insert the fuse tap harness prongs. Install the removed fuse into the second slot on the fuse tap. Route wiring out of fuse box cover (a small notch may be necessary). Connect to Morimoto fuse tap input on applicable XB LED headlights. Enjoy!