Most vehicles today. and this includes Motorhomes and Trailers. well they come with options.. For example on a RV one option is an inverter. and there may be two or 3 different inverters. Auto Generator start. and more.
Well rather than stock 20-eleven different wiring harnesses they make just one harness with a bunch of extra wires in it.. So you will almost always find wires that go no place and do nothing.. SOME of them may be "hot" some Ground some .. Both ends are N/C (not connected). You can use them if you the two ends are where you need them to go. Even if one is connected at the other end (you can cut it) provided it goes from where you need to where you need.