On my '87 4runner, I kinda had the same issue. When my gauges went out, I couldn't roll down my rear window via the cousole button (no it wasn't locked either). When this happened I blew a fuse, don't remember which one though. I had a short somewhere because it kept popping, somedays worse than others. One day I desided to just leave it alone to see what happens. It later stopped running due to a dead battery. When I new this i looked for everything, I finally ran out of fuses and just jumped the fuse terminal. Saw smoke, pulled jumper, inserted my very last fuse, and it has been operating fine ever since. After my rebuild I noticed that the wires comming from the intake manifold harness area to the trasmistion area were burned, (my reverse/4wd indicator lights I think) were massivly torched. So I am guessing that is where why sort was, but I'm not for sure.

I don't know what to tell you about the seatbelt though, that's where I vary from yours.

Good luck,
GOI