Replace your flasher, you'll have to remove the light switch to get to it. Search the forum for a more detailed guide.
=======================My turn signals randomly quit working. Ill turn either side on, and sometimes they will work fine, other times they just stay on for a few seconds then shut off. Bulbs are fine.
Pry headlight switch? My 98 Deville is intermittent. Clicker making an odd sound, like relay chattering whenI would try replacing the flasher I had to in mine because the turn signals quit blinking and stayed solid. with the new flasher it works fine. The part was relatively cheap I believe it was $15, I had to buy it off ebay they didn't have it at autozone. It easier to get to it by prying out the headlight switch then taking apart the dash