Check this web address--the instructions work for electronic flashers. It's better than using resistors (it uses an el-cheapo relay)--it maintains the low voltage benefit of using the LED's, which means you can leave your hazards on for longer periods if you break down. Isn't reduced load, even if only a few volts, always better?

http://www.mesa4x4.com/tech_articles...flasher_2.html