fusible link?

[armyhorse86]

i was out wheeling my 86' b2 the other day, everything was going good had no problems whatsoever, i shut my truck off to take a break but as soon as i went to turn the truck over i had nothing, the truck was completely dead. i checked out the solenoid by touching the two copper terminals with a screwdriver, as soon as i did that the truck was trying to turn over but there was no fuel pumping in the system. so in the end i cut and spliced a piece of wire that i had laying around and hooked it from the battery to one of the alternator wires, after i did that the truck starts up like nothing happened. i was able to make it home but now im wondering if its the fusible link that is causing the problem, and why it would cause a problem. when i got it home i cut and spliced an extra set of wires that came off of another harness i had, the truck started up fine but yet again when i shut it off nothing came back on. does anyone know what is causing this???