I'd start with a test light to see if you're getting power to the socket.
It MIGHT be that you are getting power but the socket is corroded or the
connection points are not making contact.
hi there. i have an 86 wagoneer and im having an issue with my
drivers side rear tail light. it seems to not work (yes ive checked
connections and bulbs). all other break light and blinkers work, for
some reason the tail/parking light doesnt light up. not an expert but
need to resolve this issue asap. troubleshooting/repair suggestions?