I recently bought some LED replacement tail lights for my wife's Focus SE. I got them on Superbrightleds.com, and they recommended using load resistors. I've seen a few threads on here about questioning which wires to use. After taking my volt/ohm meter out of it's holster, I found the correct wire combo to use this evening. On both sides of the vehicle, use the black with white stripe as the ground. The driver side uses the white with black stripe as the flasher + and the passenger uses the purple w light green stripe as the flasher. Basically at the connector to the bulb it's going to be the 2 outside most wires on the 3 wire connector. Polarity doesn't matter however when hooking up the load resistors which keeps your turn signals from rapidly flashing.