Checked all grounds, everything looks fine. Cleaned all corrosion out of the problem socket and reinstalled the bulb. Presto! Except now, it's too bright! Upon closer inspection, the wrong/brighter filament is illuminated with the lights on. I'm guessing this is the brake light? Don't understand how all other taillights are fine but this one is acting wonky. It is the closest light to the rear harness. Not sure if that matters. Ugh. Back to the drawing board.
1968 Impala SS