I'd like to thank Spencer for being right on the money...
This little fuse here:
ended up having some corrosion on it. The spades on the fuse looked pretty decent but the connections inside that the fuse pushes into had some corrosion. Not much but a very little bit of discoloration. I got them all cleaned out, cleaned the fuse, and voila - suddenly the whole system works again.
Stupid car.
What's funny is the old 77 scout's fuse box looks like it suffered a mild fire that was put out with salt water and has never had so much as a hiccup. Ridiculous.
I'm now absolutely certain that Mild Overhaul #2 scheduled for next winter will include removing the central locking system and the immobilizer along with a good old fashioned ECU reflash to free up some horsepower.
Meanwhile, all the connections were lubed up good and deep y'all (read that in a southern accent) in dielectric grease. I'll seal the living shift outta the box with Vaseline or something tomorrow before tossing the seat back in.