Finally got my truck fixed. I had to take it back to them once the part came in, as it was no need for it to stay there when I could use it. As it turns out, the problem was cause by a corroded wire coming from the module. Apparently a rodent or other vermin nibbled at the insulation, possibly before I even bought the truck, and the wire finally corroded enough to break the circuit. All was repaired and it's driving like new.
Side note, a friend of mine was telling the story of test driving a new truck, and when they opened the hood they found that something had been having a field day with the under-hood insulation.