Generally, a stock automotive Turn Signal (or Hazard) Flasher Relay does not work with LED Bulbs unless it was designed for that.

How does a LED turn signal flasher work?

It's that current flowing through a bimetal that completes the circuit and turns on the front and rear turn signals—that current also heats the bimetal strip, causing it to bend and open the circuit, which shuts off the lights. The strip cools rapidly and the cycle repeats, making the lights flash.

Are all flasher relays the same?

They come in a variety of shapes, sizes, and designs, which will vary according to the specific needs of the vehicle. When current is applied to the relay the circuit inside cuts on and off, which results in the clicking sound of the relay, as well as the flashing of the turn signal or hazard lights.