You may want to find a Ford Electrical / Vacuum Troubleshooting Manual, which I think is produced by Helms, Inc. I think Helms still sells them, or you could find one on eBay (I bought one for $13 on eBay). This has electrical diagrams for each and every system, along with troubleshooting hints.
If that isn't enough for you, you may find more info in the full Ford shop manual, also from Helms. But that will cost more than the EVTM.