How it works: The stock headlight power connector (5) powers the relay (6) which provides power directly from the battery (3 & 4) through a fuse (7) to the HID ballasts (1 & 2). Got it? Keep in mind that a Relay Harness is only necessary if your HID retrofit kit is a 50 Watt or higher kit.

Understanding the Context

A Relay Harness is NOT necessary for 35 Watt kits.