This probly isn't wut you expected when i said "hard to do", but, I CANNOT FIND a definition of wiring harness on the internet. I don't know what it does and I don't even know what forum to ask this question under because i don't know what it is. Would someone be able to explain wut a wiring harness is?
That what it is. When you take out your head unit the wires are all in one plug. If you cut the plug off you don't know what the wire go to. The wiring harness has what each wire goes to on the wires. You just unplug the head unit and plug the wiring harness in to it. You can find what each wire goes to on the net or by doing some tests. Also you can run all new wire but the wiring harness is the easiest way to go.