To get maximum power from your headlights it is recommended to have the shortest possible distance between the power source and the bulbs. Stock headlight wiring is not designed to handle halogen headlights, especially when upgrading to a higher wattage. Running the power through a switch is an even worse situation. Resistance in small gauge wire or in the switch will lower the output at the lamp. Be safe. This headlight harness draws power directly from the battery, through a relay, to the headlights, thus providing full power to your H-4 conversion headlights or halogen sealed beams. It can also be used to relocate headlamps to a remote location when using a snowplow. Made with TXL high temp wire, waterproof 30-amp fuse, and two 40-amp relays capable of handling up to 150-watt bulbs. For use on vehicles with a 2-headlight system using dual filament sealed beams or H-4 headlight conversions.