The library usually has some good resources for info. Here I have been able to find all kinds of wiring diagrams. You need to ask not just look for yourself. I have found some of it is not check outable and is then behind the counter. They will usually make a copy for you. I am an electrician by trade and I have found the best way to trouble shoot a ground in a car electrical system is to get a 12 volt light bulb, solder wires to it and put it in place of the fuse. If you have a ground it will light up brightly. When you clear the ground it will either go dim or out. Keeps from blowing fuses. That can get real expansive.
Wiring diagrams and component locaters are invaluable when doing electrical work but they won't always lead you to the part that the monkeys with 8 miles of red wire and a roll of black tape screwed up. Why not start by having the "kids" undo what they did, it might make your task easier.