The best/cleanest way is to drill a hole at the bottom of the roll cage, and at the point closest to the light bar, and fish a string through the cage and pull the wires thru. It's kinda a pain, but the reward of a good clean install is worth it. You didn't mention what vehicle you are installing on, but I know that the new "non round" roll cage on the 900's and 570's are a pain for running wiring inside, but I managed to do it for my 6" reverse light that I mounted on the back of the roll bar. The traditional ROUND tubing roll bars are a lot easier to fish the string and wires through.