Hello, 1991 4.3L TBI 4x4

Problem: When you turn the dash lights/running lights on, the Right turn signal dash bulb lights up. It stays lit up, but it will BLINK when you turn on the right turn signal. It is not lit when the lights are on, but will blink with the right turn signal on.
Its wierd.. Any ideas?

 

Sounds like corrosion at one of the lights. I would start by taking the marker/turn signal lights apart and inspecting the socket where the bult plugs in.