Brake lamp issue

[Isaiah92260]

Was told my tail lights don't appear when stopping. Checked all my connections with a test lamp. Fuses are good, even replaced them just to do it. Brake switch is responsive. But when pressing the brake pedal, no power coming from the black power wire. When I turn on the light switch. I got rear lights and power running through the black wire. Brake lights just don't work at all. Can't figure out why?
I have a 63 c10. Please share some advice or expletive. This is my daily. Thanks !