Car system diagrams

Wiring diagrams are published in auto repair manuals. You can buy one from Ford for big bucks or buy manuals at auto repair stores and book stores or many libraries have them in the reference section. Usually they won't let you check them out but you can find what you want. Here is Chilton Online. I haven't used them and It's my guess is that you have to pay for downloads.
Chilton Auto Repair Manual Online

cheapest way to get one is buy the owners manual for your car I think Chilton's repair manual is the best cost around $20.00 at most auto parts stores call around not all auto part stores have Chiltons but Haynes repair manuals have wiring diagrams too, make sure it has the diagram you need prior to buying

buy an owner manual at most auto parts stores for about $20.00 best I have found is the Chilton's repair manual call around not every auto store has the Chilton's manuals (best wire and vacuum diagrams and diagrams for many other systems in your car)

I found the best wiring and vacuum line diagrams in the Chilton's manual I bought for my truck call your auto parts stores to see if they have one not all auto parts stores have Chilton manuals these manuals have diagrams for most all systems in your car or trucks

If you purchase a repair manual it will contain the wiring diagram. Your local auto parts store sells these books. They may have to order the one you need. Also any book store can order what you need.
Two publishers are Chiltons and Hayes.