1990 Silverado 1500 2wd Left Taillight Not Working

[SnakeEyeSS]

The left twilight on 90 C1500 isn't working. fuse is good, circuit board on the taillight looks new(light assembly is only a year old), all the lights are good. terminals on the board and the wiring harness are clean, even sprayed one WD-40 on the to make sure and it had no effect. no brake/turn signals/talights. I know this is a common problem(know others with teh same issue, replacing everything sometimes works, but usually temporarly) but there doesn't seem to be a common solution.

[Draenor]

Have you taken the board off and tested the connection with a multimeter? You need to start there ,to see if you are getting power. Then go from there.