69 valiant electrical gremlin turn signal and license plate light

So i took the passenger side light off and plugged in the suspect from the drivers side. The EXACT same thing happened. Headlights on no blinking but light stays on. when headlights are off; blinker works fine. I then plugged in the original passenger light again and it functions 100 percent correctly. Can the turn signal housing assembly go bad? it is weird to me since i could replicate it with moving it to the other side. deduction would say that the problem is in that assembly but there does not seem to be much to it. Could it be the bulb? i know crazy talk, but...