I think I traced it to the light socket. I can get it to light by wiggiling the wire. The contact inside doesn't look healthy.. I ran new wires for the turn signals, 2 diffrent colors so I can tell them apart.

The ground is what I first thought of, and I manually touched the light socket with bulb to the trunk latch, and that's where I found by wiggling, it will light. The original wire for the tail light on that side looked not so great, so I tied it into the license plate light wire ( All shrink and solder, no butt connectors ). It has good power now. can't test the brake light power without a helper. If I can't get the brake light to light that side, I will tie it directly into the stop light switch. Right now, the switch is wired in the factory way, just the wires are extended to utilize the pressure switch.. But now I have to figure out where to find the

I have a couple 36" test leads that I will make longer to test the grounds further. I was going to buy Alligator clips and make my own but the pkg of 4 alligator clips was $2 and the 36" assembled test leads was $1.50.. The only complication I have now is finding a socket to fit. There the spring fit- click in style and I know I could add a basic dual filliment socket but I would loose the ability to remove the bulb without removing the backer plate. If it gets me out of a pinch it may be just what I do, as I have 1 on hand but only if I can't find the right thing. removing those 2 screws and getting them back is a PIA with how far the tail lights are stuffed into that corner under the trunk lid. Chevy didn't make it an easy car to work on in the sense of how/ where things are located, but it is very simple in how it functions.