91 firebird electrical issue

So, one day I started to drive home and when I
went to turn my head lights on, nothing happened.
No noise, no actuator, no lights, no interior lights,
no dash lights, nothing. After I stopped to check
some fuses, I realized the interior lights weren't
coming on when I opened the door. And the cigar
lighter wasn't working either. And neither were the
trail lights. Break lights, hazards, back up lights,
blinkers, radio, windows, windshield wipers, power
mirrors, and pretty much everything else still
works.
When I got it home,I took it apart to check the
fuses. Everything checked out fine. Not a single
blown fuse. Then I checked the convenience box.
Still, everything is fine. Checked the head light
switch and it looks fine.
I don't really know what to do other than to start
going through the whole wiring harness and
checking for shorts or loose grounds. Can anyone
help me that's also had the issue?