So LED's don't burn out, but it seems they can go bad. I have some proof. I'm not sure what exactly went wrong, but there are six white LED's in this taillight set-up. They were actually a little too bright. So when one set of three quit, I assumed it was a bad solder job and didn't worry about it. Then the other set started flashing, I again assumed a bad solder from somewhere in Asia was the problem. I decided to try and fix the problem this time.
This is what I found. If I jumped across one specific LED that LED quit and so did the flashing.
I decided to play with the totally dead side, too. Again jumping across one LED made the others work. It was actually the LED on the exact opposite side of this cluster compared to the flashing cluster.
Cut out the questionable LED and put a dot of solder to complete the circuit on both clusters.
Working good and still plenty of light on the tag. I'll keep an eye for sure though.