We wouldn't attempt this without the factory manual. It will give you the correct color codes for the wiring and where each is meant to go. The book comes in handy when deciding which wires can be left unconnected and which can be removed or left unplugged. Keep in mind that the newer the system, the more complicated the conversion. On some vehicles every electronic gadget is monitored or run through the ECM. If one wire is improperly connected or missing, there could be problems with the performance of the vehicle. For ease of installation, once it's determined where a wire or plug goes, it should be numbered, along with its respective component.