[Steve in Denver]

For 12V, there is a flasher that works both with LEDs or regular bulbs, or a combination of both, Novita EP34. Autozone had them for around $10. They do not depend on current draw, but rather must work on a timing sensor of some kind. The EP34 works with 6 bulbs, the EP35 works with 4. I recommend the 34 as you need to count any bulbs you have on the dash that indicate flashing.