This D1S/D1R ballast uses a socket integrated ignition coil for the high voltage pulse generation. Each D1S bulb requires a D1S ballast of its own, even with the ignition coil being integrated in the socket. For many vehicles, the input wire that powers the ballast will be different. You will be required to cut or spice into your factor connector to power our ballast. Also note the shape and size of our ballast maybe different than yours and may require special mounting.