I've committed myself to restoring my '69 Cobra Jet, and I'm starting with the wiring. The wiring was messed with before I got the car, so it doesn't appear to be completely factory. Each tail light has a ground wire attached that doesn't appear in any diagrams I found, but I tested with a multimeter and it appears each one is grounded (If this info helps). I realize this has been posted alot, but I'm not sure where to start. All other lights function normally (minus a headlight and reverse light bulb that are out) except for the left rear brake light. It lights up when the headlights are on, but doesn't light up for braking, the turn signal, or hazards. The front left turn signal also works normally, and there's no problems with lights on the dash. The left bulb worked when I put in in the right side but not vice versa, so the bulb's not the problem. I'm unsure whether (or where or how) to try to find a ground elsewhere, replace the signal relay, or check the turn signal switch.