Installation: A relay harness connects your HID lighting system directly to the car’s battery. … The main benefit of installing a relay harness is that it can help to provide a regulated flow of energy to your HID headlights.

Do HID bulbs need a resistor?

Necessity – One resistor is required for each turn signal bulb, license plate light bulb, etc.; as well as HID bulbs. (two per side if using hi/lo).

Why do my HID lights not turn on sometimes?

If one side sometimes doesn’t turn on it could be caused by a bad bulb, HID ballast, LED driver or wiring. … Swap the ignitors to opposing sides (not applicable for LED kits). If the problem is reversed, you might have a bad ignitor. This step will check if you have a bad ignitor.