Turn signals not flashing

I have a problem with my turn signals not flashing. When I turn the indicators on the lights will turn on but not flash. This happens to all of them left right front and back. I checked all the bulbs and replaced the flasher relay with a new one and the problem stayed the same. What should I be testing next?

Is your battery fully charged? When my battery was not fully charged the stock relay wouldn't make the blinkers flash. A fully charged battery helped, but what totally solved the problem was replacing the stock flasher relay with a modern electronic unit (about $9). The electronic units do not require a fully charged battery to make the blinkers flash. Ed