I have a '17 with Anzo and switchback LED blinker bulbs. I have implemented the via forscan the permanent blinker on for the Anzo LED's and also the code that removes the hyper flashing. I've been running this setup for prob. ~3 years. I noticed recently that my left blinker wasn't flashing, it keeps with the solid white light. My side mirror and rear light does flash. I assume this is a faulty switchback bulb and need to replace. Is this a correct assumption or am I missing something simple?

 

Yes I would start with the bulb replacement

 

Switch your other bulb in and see if it fixes then problem, if so, you've found the solution, a new bulb.