Fuse 3 and 4wd question

Hi everyone - new here hoping to get some advice to get this truck back going

background - 4wd used to work sometimes, but got to where it would never work

transfer case shift motor was not operating

when moving the selector switch on the dash there was no clicks or anything

pulled the switch out and unplugged it to check the wiring harness for power with a test light, none of the 4 wires had 12v power, should one of them been hot?

also, the fuse 3 under the hood, fuse was fine, but no power to the fuse - all of the other fuses in thr fuse block had power testing with test lights but not the #3 slot

anyone tell me what send power to that slot?

everything else works on the truck - cruise control, ac, windows, locks, etc - is it possible that the gem could be bad and the only thing not getting power or working is fuse 3 and the 4 wd?

whats the best repair manual For wiring schematics troubleshooting that I can purchase and download That yall reccomend?

thanks in advance -

There's a dvd repair manual on eBay for expys it's more complete.