If you use a H4 HID (high-intensity discharge lamp) system in your vehicle then you may well need a wiring harness to ensure your headlamps are lighting fully and uniformly. The harness connects directly to your battery, thus avoiding the problems caused by the lamps taking their power from your vehicle and then shorting the electrics. It is for use with either headlamp. Specifications:
Works with any vehicle that uses a H4 HID lighting system to ensure the battery power runs directly and smoothly to your headlamps for a even and balanced glow