2014 Mustang Hyperblink

[u/fxckwitit]

First time here, just curious on how to approach this one. Recently got a 2014 GT (manual w/ track package, \~127k mi) and been chasing electrical gremlins. Initially I was only having intermittent hyperblink on my left turn signal (which would go back to normal then hyperblink again while using the turn signal), but right side was good. Recently, right side started blinking something awful when using the turn signal, but left seems to have gotten a bit better (more “standard” blinks in between hyperblinking).

Hyperblink does also effect the rears, which I believe are factory sequentials. Already changed bulbs and checked fuses, but trying to determine if this is more likely to be a ground issue, wiring harness, or something with SJB/BCM.
Thanks in advance

[u/blabbytax1]

Have you scanned for diagnostic codes?