89 Chevy electrical issues

[SlyRado]

My 1989 c1500 is having wiring issues. The headlights, Interior lights, Horn, Cigarette lighter, Radio all of it does not work. It all went out at the same time. From what I’ve seen all fuses work only odd thing I noticed is one of the relays under the dash is not getting power where it plugs up. If you get the yellow wire from the radio wiring harness and connect it to the red wire it’ll back feed and everything will have power that way which is weird. So I assume some circuit is completely dead and I don’t know what is causing it to not work. 

[richard wysong]

Probably a problem in the underhood fuse box

[SlyRado]

All the fuseble links have power 

[SlyRado]

2 hours ago, richard wysong said:

Probably a problem in the underhood fuse box

All the fuseable links have power.