Rear tail lights... Only some work but not always?

[K10mashup350]

So I just replaced me taillight harness from fuse panel all the way back to the lights (including the "t" for the actual lights) so "technically" 2 harnesses. The reason was when I bought this truck they had every wire harness cut an hacked an almost nothing worked an the taillight harnesses weren't even there....
But my issue is that they don't work running lights work always, and sometimes(not often at all) the break and hazard (not signal) will work drivers side only and nothing on pass side. Fuses look good an flasher seems to work as the front works....

More about the harnesses I put in:
They were not new or 100% intact, I did have to "reconnect" a few locations/light sockets and I did so with heat shrink then fully wrapped the harnesses with wire loom and electrical tape to ensure no wires can come in contact with anything an "rub" to where there could be a short in the lines...
As I had all the wires "bare" I inspected them for cracks/imperfections and corrected the few that I did find, so in all aspect the harnesses are now "new" without defects.... But I still don't have working taillights....

The attached pic shows the lights that do work constantly everything else either don't work, or is a swing n a miss to if it will work.

Any help on this would be greatly apperitiated so that I can drive my truck, an be able to get my certification...

Thanks