Bad Ground....but, where?

[Davidf]

Also, to test, remove the lens and wiggle the bulb/lamp. If all starts to work properly, then again it is not a ground issue but more a socket or bulb compatibility issue. Try a different bulb/brand. Try a bulb with a copper base in lieu of nickel (colored?).

I can pull my turn signal assembly connect it to a power supply and it behaves the same way. So, it cannot be a ground issue.

Incidentally, the side marker on the side that is giving me trouble does not flash.