GM Genuine Parts Headlight Wiring Harnesses are designed, engineered, and tested to rigorous standards, and are backed by General Motors. These harnesses are organized sets of wires, terminals, and connectors that run throughout your entire vehicle. They relay information and electrical power to your vehicle's headlight switch and head lights. GM Genuine Parts are the true OE parts installed during the production of or validated by General Motors for GM vehicles. Some GM Genuine Parts may have formerly appeared as ACDelco GM Original Equipment (OE).