69 valiant electrical gremlin turn signal and license plate light

okay. Going to get alligator clips.
Now for the turn signal. I took it off and used light tester on this. With headlights on the big hole registered light and when blinker activated the little hole also worked. But when blinker was off no light tester on small hole. This was consistent with issue of blinker not working when headlights are on. Blinker just stays lit. Where to hunt next?F8D0E2F5-9637-4962-B108-614237247DA4.jpeg