tail light issues

Hi all! Lots of good info here, been lurking for some time. I have posted this on B-bodies as well. Sorry for the long post on what seems to be a common issue albeit with different twists. Recently purchased a '67 GTX clone and been sorting through previous "fixes". One that has me still stumped is the left year tail, brake and signal light. It was working intermittently and has since quit. New bulb, socket and some wiring (have a new rear harness on order). If I ground the socket I get tail but no signal or brake. All other lights work in the car. I just received a new turn signal switch today but need to figure out how big of a job for my ham hands that will be. My hope is to at least get it working while waiting for the rear harness so I can get my son out and away from the video games ( he LOVES the car)!
Author: celt69