[Slammed84]

Im not certain what year your truck is but mine is an 84' and I just went through this exact problem.
There are two wires from the engine harness that supply power to the fuse box.
One comes directly from the battery, passes through the starter lug and then into the fuse block. This wire only powers the horn, and the lighting circuits. As you know these are always hot.
The second wire comes from the battery and hits the junction block on the firewall. this junction block also has the wires that feed the lug on the alternator, but ultimately it is the power source for the ignition switch. Also the power wire for the heater relay thing that mounts on the A/C box hits the other side of the junction block.

when the truck is in the off position you should have power to lights, horn, and the input of the ignition switch. everything else i suppose would not be hot until the ignition is set to acc or run position.

i can post pics if you would like to see my factory wiring