Usually a vehicle manufacture will use there own wiring harness for there speakers and such. You can use the factory wiring but you might have to cut off the end of the factory connector and use some spade terminals to connect to the speaker.

*NOTE* Leave about 3" of wires on the end of the factory connector that way if for any reason you have to switch back to the factory setup you can just use a butt connector or solder to connect it back up.

Not sure if that helps you or not.

BTW: What kinda car are you installing the speakers on?