Many times the LED blinkers do not draw enough current to operate the flasher relay. The stock flasher is a current sensitive device. The current heats a bi-metal strip that bends and unbends to create the flashing effect. If there is insufficient current the lights will not flash. There are flashers out there that can work with any type of load, large or small. I don't have first hand info, just know from same questions on others forums. You have to figure out how to wire in the new flasher and I expect it will have wiring help included. You'll need the schematic for your application and a little trial and error.