They may actually be blinking, but the wattage of the running light filaments may be overpowering the turn signal filaments, making them indiscernible.
Another possibility is that the whizzing-in-wind guy put both tail light wire and blinker wire to the same filament.
Take off the lens cover, pull the bulbs, and use an ice pick-style test light to check each contact as an assistant turns on the lights and blinkers for you.
Carl
