Apparently, there isn't one. As with a lot of other modern Ford vehicles, turn signal flashing is controlled by the GEM (General Electronics Module), which does many things. You can't just replace a little single-purpose "flasher" unit in the FFE, unfortunately. (I replaced the flasher in my Honda Accord accord after its LED retrofit... works great when you can do it.)
But, I'm in the same boat as you retrofitting my FFE with LEDs. Strangely, LEDs in the brake lamps aren't triggering any sort "bulb out" warnings. (I used Triton V3 units from v-leds.com... highly recommended, they look like normal bulbs are in there when off.) But, as you've probably discovered, putting LEDs in the turn signals will cause "hyper-blinking".
I think the only option is using "load-equalizing" resistors. (There are lots on ebay for cheap.) Btw, I have discovered that the FFE requires resistors "on all four corners" (assuming your are replacing the turn signal bulbs both front and back).