[1project2many]

LED lights can be much more complicated than folks realize. I once had a set of LED's that would behave similar to the problem described. At one point I put constant power to the LH and RH turn connections because, goldangit, that would make the lights light up. Except that when I got to the rear of the vehicle they weren't lit. Lots of checking and double checking but it finally took me getting tired of walking to ask a helper to watch the lights. "They're on. Wait, they just went off!" But I never did anything that should have turned them off! Turns out they would light for a few seconds and shut off. Bad connection? Bad chip? I dunno. Parts store only said they stopped selling those lights because they had too many problems.

I do not believe LED's should be treated like simple light bulbs. They are complex circuits sealed in plastic or epoxy and often cannot be tested internally. An incandescent test light is great to confirm the rest of the circuit is good. Then suspect the lights.