I normally enjoy the satisfaction of problem solving, and have been working on this one till smoke comes out of my ears, and thought that I had better call upon my fellow bricksters before I do something stupid. The clues:
no right rear tail light (all lights in the front work)
no dash lights (instruments work)
gear selector light works (automatic trans)
seat belt indicator light has always occasionally blinked on
what I have done
checked voltage at right rear tail light .48 volts
checked voltage at fuse 16 11.8 volts
probed yellow (r.r. taillight wire)at bulb failure warning sensor .44 volts
swapped bulb failure warning sensor with known good unit (no change)
opened parking brake console to inspect, unplugged r/w wire harness to seat belts

I am running out of ideas, but in my research I found a post by "springlizard" with a similar problem who solved it by "reflowing the solder on the instument cluster" would love to hear some more about the details of that fix! Also, I managed to find a link to a site where some saint posted the following pages: