If everything is totally dead, just as if there was no battery in the truck, there is either another fuse link wire burned open or the wires are connected to the wrong places on the starter. GM likes to use the starter terminals as convenient tie points for multiple circuits. That saves on wire but it can lead to some confusion.
Start by looking at the large terminal on the starter solenoid that the battery cable connects to. There should be other smaller wires connected there too. Sometimes they fall to the side and get overlooked when they've been removed. When you find them, there will be fuse link wires starting at the terminals. Tug on them gently to test them. If they act like a wire, they're okay. If they act like a rubber band, they're burned open.
Next look at the smaller wires on the small terminals on the solenoid. There should only be one wire on the "S" terminal. If you have a second terminal, marked "R", that should also have only one wire.
Check the two negative wires from the battery. The fat cable must be bolted to the engine. The smaller wire must be bolted to a rust and paint-free point on the body. If everything up to this point is okay, you'll need a test light or voltmeter, then we'll start with some diagnostic tests.
Tuesday, March 31st, 2015 AT 8:58 PM