60-66 full body wiring

[TotalNewby]

Looking for some help!

I have a 64 C20 with rear light issues. I have turn signals but no brakes, running lights. Also, I have no interior dome light, but gas indicator works. I have replaced just about everything with no luck. Starting at the back, new bulbs, new wiring harness all the way to the front, new brake light switch, new dome light and wiring, new director signal connector in the steering wheel. The onyl place I can see on the wiring diagram where dome light and rear lights meet is in the light switch connector. I am not sure what/where that is or even what it looks like????? Anyone out there got any ideas? I am stumped!!

THANKS