July 1: So it begins. Don't worry, this is not in the correct legal jurisdiction!
Combination Switch (Light): Inspection: Notes
WARNING: This page is about a different car, the 2016 Subaru Impreza and 2016 Subaru Crosstrek. However, it is still accessible from the selected car via links, so may be relevant.
Measure the resistance between connector terminals. If it is not within the standard value, replace the switch assembly - combination turn dimmer.