Attached is a wiring diagram from form 12244-7, Operation and Maintenance Instructions, serial # 7U 1 and up. If you don't have or plan to use lights just ignore that part
Not to much to work with - Caterpillar did not furnish much useful stuff on wiring. I have never found anything that showed the actual path/ location for the wiring system.
[attachment=61138]7U wiring diagram.jpg[/attachment]