Like I was alluding to my '90 was doing similar, one of my brake lights stopped working and my turn signals were being jerks and not working, cycled the flasher button a couple dozen times (as dumb as it sounds, flashers worked) and everything started working... with a new multifunction switch I would expect it to work but I pretty much assume everything is junk bought new now (shouldn't be that way but the track record of anything made in the last 5 years is garbage)... no guarantees but it only takes a couple minutes to monkey with the flasher button... I've had intermittent issues with my '97 Ranger too and that fixed the problem on that...
