First thing I'd do because it's easy:
Do the 4x hazard flashers work?
Then swap the flashers and see if the turns now work.
You can pull the turn flasher and jumper across the flasher connector. This will cause the lamps to stay on solid when you select turn, and will show that the TS switch, wiring, sockets, bulbs etc are OK
Do both brake lights work OK?
Suspect the TS switch
