I'm lazy, and I just leave you people all hanging and whatnot.
Shawn's truck is fixed. It has been fixed since like a couple days after I posted the post about it being broken.
It was stupid simple.
The little metal connector thingy that connects the ignition to the glow plugs was busted. It's the thing that always broke on his dad's car. When he moved down here, his parents gave him an envelope with like 5 of these little connectors in it because "if your truck ever doesn't start, but the starter sounds like it's turning over, it's probably this connector that's broken. Replace it and you'll be good as new." Price of the connector: Like $5 for 12 (I'm guessing). Equipment needed to replace connector: Phillips screwdriver. Time to replace connector: 5 minutes or less. Time it took for Shawn to diagnose this was the problem: 8 days.
To be fair, the connector was the first thing he checked. It didn't look broken, so he didn't think it was the problem. It took 7 days before he decided to take a better look at it, and that's when he noticed it was broken.
But I still think the Prelimbs thing is stupider.