Not sure where they are (easy to find out; stick the hazards on and listen for the clicking relay...), but how would you get a flasher relay designed for LED bulbs? I didn't know they did various types.
There are the old fashioned ones that work on the resistance generated by having 2 or 3 bulbs working. Hence when a bulg stops working, the remaining bulb(s) flash twice as fast.
The other type for LED's isn't like the above (you can see how great my technical knowledge is !) and generates a pulse that will work.