75 Caddy Fleetwood Limo

Hi everyone
I am the proud owner of a 1975 Fleetwood 6-door limo. The tail lights aren't working - back-up, brake & flashers are all fine. All wiring checks out for continuity, HOWEVER I don't have any power to the connector in the trunk that feeds the tail lights.

The front parking lights and headlights come on fine, also...

My shop manual was drowned in the trunk, so am a little short on info and schematics at the moment. Sigh!

Thanks in advance
Veronica
:confused:

No easy answer here, check the wire coming out of the h'lite switch for 12v, then go to the next connector and keep going along the line looking for an open circuit or corroded wires.