wiring problems ??

[77f-250]

I've got a 1979 ford f-250 4x4 with a 360 and c6 tranny (76 running gear) im trying to figure out the brake lights. I checked the brake switch on the pedal and no power there two wires simple enough, one lead me to the turn signal fuse, so i wanted to trace the other one but the wires been spliced into several different colors and i cant chase it through the firewall and was wondering if someone knows where the other wire ends up at.Then i have no dash lights checked the bulbs are blown so need new ones of those so i swapped a few used ones in that still work. Played with the dimmer switch followed some wires and am kind of lost at what it could be. and last does anybody have a wiring diagram from the cab back that i dont have to squint and hunt for the plugs?? Thanks for all the help.

[mikeo0o0o0]

Here you go, factory wiring diagram 1973-1979 Ford Truck Wiring Diagrams & Schematics - FORDification.net