bought a new to me truck yesterday. craigslist deal, traded a trailer i had no use for in the foreseeable future. pulled a 3/4 ton diesel truck home 22 miles with a 1980 bronco with a straight 6. long long drive

truck is a 1995 F-250 7.3L DI 2WD regular cab, long box, dual tanks

PO said that the fuse for the glow plugs had blown and he hadn't had the right so fuse so he replaced it with a larger (50A) fuse. the story seemed shifty from there. short version was that they cut the two wires going to the fuse box for the glow plugs

when i got it the distribution box was disconnected. the wires for the glow plugs were cut (red wire with a thin green stripe, one appx 10ga, one appx 14ga) and the yellow wire feeding the distribution box was disconnected. i checked the thicker wire with a multimeter. reading was 0V against the negative battery terminal, 13.4V against the positive terminal.

truck turns over fine, and most of the accessories seem to be working (radio isn't coming on, cab lights didn't work, etc)

shouldn't the thicker wire be a hot wire? it was reading as though it were a fully grounded wire. Does someone have a good wiring diagram i could use while chasing this down? the dash gauges aren't reading, so i'm going on the assurance of the PO that the tanks both still have fuel in them. any good method to ensure that fuel is getting to the engine? I'm open to suggestions here.

i brought this home telling my girl "no worries babe, i'll have it up and running in an hour..."