Not starting

It sounds like the engine may have locked up. Can you use a large breaker bar and socket on the front of the engine to see if it turns over?

Please let us know what happens.

Cheers, Ken

Try unbolting the starter and then see if it will turn over off the truck. Also, see if you can turn it over by hand.

The second wire feeds power to the rest of the truck through the fuses.
When it dies does everything (lights, dash, radio) just shut off, or is it just the engine?

So just the engine dies, but it will start right back up? Do you have to wait at all from the time it dies to restart or can you just kick it into neutral and restart?
Does this happen at random or does it have a pattern? Such as it does it mainly after you turn a left hand turn, or it dies around every 20 minutes?
When it dies does it just shut off or does it seem to "run out of gas"?

Alright, As it starts right back up and dies fast I don't believe it's a fuel related issue.
That leaves ignition power and likely a bad connection or wire. So start it up and pick a wire to something like the ignition control module and start GENTLY moving it at any connectors it has. The idea is to see if you can find the wire/connection that has the bad contact. It's a pain but on intermittent issues without a long "off" time it's a starting point.
Also try starting it and gently moving the key around in case it's a worn ignition switch that barely breaks contact.
Check up under the dash as well. A wire could have rubbed through on a steering shaft or brake pedal and shorts out.

Hi guys. If I could interject a comment of great value, you might consider adding a wire that you can run into the cab and connect to a digital voltmeter or a test light so you can see what is happening when the problem occurs. An easy point to start at is the ballast resistor on the firewall, under the hood. It is usually fed with a dark blue wire, but on some truck models that was a red wire. If you have the older dual resistor, the two terminals on one end will be connected through a short jumper wire. That is the end that gets 12 volts from the ignition switch, and is a good place to start. Run the wire from that resistor into the cab, but be careful that it is run in such a way that it won't get cut by the hood. Knowing whether the light goes off or stays on when the engine stalls will tell us which way to move to next.

If it's easier, you can connect the test light to the dark blue, (or red) wire on the alternator too.

The second wire at the starter you were asking about is to run the built-in starter solenoid. When you turn the ignition switch to "crank", it turns on the very small current that turns on the starter relay. The starter relay turns on the medium current, (about 15 amps), that turns on the starter solenoid. The solenoid has two functions. First, it electro-mechanically moves the starter's drive gear out to engage the ring gear on the torque converter which is bolted to the engine. Second, once the drive gear is engaged, the additional movement of the solenoid turns on the very high-current switch that passes current to the starter, (about 150 - 200 amps). That solenoid wire is usually light or dark brown and is considerably fatter than most of the other wires on the truck.

That still sounds electrical. Possibly a bad ignition switch harness or switch itself.
The radio, wipers and turn signal switch are all fed from the same buss in the box, they are fed from the ignition switch. If the switch was failing it could "repair itself" when you turned it off and back on.