last min thought, stinking rodents, mice to other, to simply vibration and insulation rubbing off in very ugly spots you may never be able to see let alone get to.
multi meter or a test light, with aligator clips, to different size pin ends, to test wire harness plugs. different sized solid wire, with dremal sanding bit to round ends of solid wire some. can help get into the female end of the plugs. i have been known to buy cheap test light kits and like. and butcher the stuff for the ends and splice the wires together, to get what i need. it looks ugly, but *shrugs* what ever gets the job done. with tractor battery disconnected, i have butchered a kids toy, for the little 9v battery plug, if i needed to test with a little bit of power, and use of a test light.
if a test light is a LED, be fore warned, it will only light up, in one direction and not the reverse direction.