To all that have a 2011 F-150 with turn signal issues (non LED bulbs). I had a rear turn signal light that wouldn't flash. It had power, the front signal fishesf as well as the side mirror. All other lights functioned properly. I ran test, changed bulbs, as well as sockets to no avail.
I was able to correct the problem by resetting the module that controls the system (I think it's called BCM). Once I reset it (by simply disconnection the battery sur approximately 40 - 60 minutes. All the lights worked properly.
Just sending ito the information in case anyone needs it. I pray it's helpful to all.