What??? There's a 3rd manual? I have the factory ones, it's a 2 volume set... one for engine, the other for body and electrical. What's the 3rd? Didn't know there was another one....
Yep, since at least the 70s if not earlier all Fords have three manuals. Engine, Body, and Electrical & Vacuum Troubleshooting Manual (EVTM). Body seems to be most rare and is most expensive. There is also an apparently official supplement on rebuilding the E40D from TechTran in later years (my book is 1992, matches my truck and service manuals.)
What is really annoying is that the body book has a section labeled power distribution but it doesn't cover fuse locations at all and only one of two blocks is even covered (the one in the truck.)
IMO Nissan has the best manuals in the industry, even in 1989 the manual is vastly more legible than my 1992 Ford books, the diagrams are superior both in what projection they chose (i.e. you will get a view of a part from an angle at which you might actually see it) and in the quality of the diagrams, which are produced AT SIZE for EACH ILLUSTRATION instead of being scaled to fit the book from whatever arbitrarily sized piece of paper it was originally drawn on. Ford is somewhere down near the bottom
with lousy manuals with lousy tables of contents, bad diagrams, et cetera. Mercedes is even worse since instead of diagrams they have bad halftone pictures, so don't feel bad
Mercedes also uses multiple books, and the whole set costs maybe $200 or more. Subaru is just as bad and the books cost even more because they're relatively rare, they have the lowest production of anyone who sells cars in the US.