AM1 fuse blows immediately
 

Been having some electrical issues lately with my 1994 pickup 22RE and can't seem to track down the solution. The other day I was driving along and everything shutoff, except the engine kept running. Radio, dash lights, gauges, headlights, no power to anything. So I pull over and shut the engine off just in case. It wont start back up, no power at all. The 40A AM1 fuse had blown, so I walked to the parts store just a half mile away to grab a new one. Didnt even get the fuse all the way in, as soon as the terminals touched it blew immediately. Did some research and the AM1 runs starter, ignition, and ECU circuits. Well a few weeks ago the starter bolts had backed out and the starter almost fell out so I thought maybe the solenoid had a short in it which would cause the fuse to blow. Replaced it with a reman one but still nothing. Fuse pops as soon as it touches the fuse block. So its not the starter and not the ECU because the truck was running fine until I shut it off. Any ideas on where to look next? Thanks for the help.

It wasn't the starter; your fuse blew (blows) with the key to "OFF." Here's the power diagram from the '93 FSM: http://web.archive.org/web/201204170.../2powersou.pdf (there are slight differences by year and market, but almost all of it will work for you). Every circuit powered by AM1 has its own fuse, so your short-to-ground must be somewhere between AM1 and the smaller fuses. Like right at the ignition switch. Or maybe inside the fuse panel in the cab.

Since your short manifested itself while you were "driving along," it wiggled/bounced its way into existence. It might wiggle out of existence ... for a little while. So rather than go through a box of 40A fuses, get a reasonably high-current lamp (like a headlight bulb) and insert that in place of the fuse. Wiggle your harness until the light illuminates, and you've found your short.