LED signal light issues.

You need to replace the existing flasher with it. There are two, one for the turn signals and one for the emergency flashers. You need to replace both if you want your emergency flashers to work.

Polarity could also be wrong if the bulb has a plastic socket. If it has a metal socket that gets ground through the body it will be correct.

When I replaced my dash lights with leds the dimmer stopped working. Not enough current. I was going to add a load resistor, but figured out that if if left regular bulbs in my aftermarket gauges, everything worked fine. They provided enough load for the dimmer to work. You could leave some regular bulbs in as an option.

I applied the same trick to my house lights. When I changed to led bulbs (even the dimmable kind) my dimmers didn’t work right any more. I found that if I left one regular bulb in the light fixture, the dimmers worked great again.