So check this out. I've been driving for a couple of weeks without tail lights (brake lights work) or dash lights. I finally had the time to dig around and after a bit of frustration this is what I found. I never would have found it if it wasn't also tied to my buzzer. I was wiggling everything with the headlights on and kept hearing it. I'd take things apart, mush pull and all kinds of stuff but it was my forearm grazing the connection that made it intermittently yell at me.

http://youtu.be/tTZQDnkdiTE