A resistor in my LED tails went out and I was getting hyperflash on the right blinker. If you install Switchback turn signals this will cure the hyperflash as well. Got to Napa/Carquest/vatozone and buy relay EP-27L ( the L is for LED) Take off the cover underneath the steering wheel. (7mmx2) Take off metal plate (8mmx4) Find the relay on the left side with the blue plug. If unsure, turn on hazards and listen to it clicking. Replace with new EP-27L. No more Hyperflash! Best part is the other side still blinks normally.
I did this very same upgrade and posted a DIY guide on the other F150 forum that I used to belong to. They don't sell the EP27 flasher module locally so I had to order mine. The less messing around you do with wiring the better.
Easy fix Will. EP27 Timed circuit flasher. They want around $16 retail for one around here. Being me I would just replace the 6-10 ohm resistors. I've seen some people who are scared of even dropping the lower dash panel.
http://www.fordfullsize.com/forum/f72/taillights-401/ Been a while since I've read it, but I have plenty of time now.
