I'm in a similar situation: turned the key to get a "splat" of wiring short, and now everything is dead. Not sure where to start, but I'd sure appreciate a wiring diagram Tony. My email is "ejfletcher AT gmail.com"
To contribute some info to this group, a 1,267-page service manual for the Ford 4100 (and others) can be bought from eBay (http://stores.ebay.ca/Hard-To-Find-Tractor-Manuals) for $130. I don't have one, but with repair costs climbing, maybe I should consider it...
Eric, April 2009