Judging by what you said you've checked, I'm a little stumped. I was looking at the wiring diagrams (I've attached a copy of the page below) and I notice that the power for both the hazard flashers and directional indicators runs through the hazard switch and then through the turn/hazard flasher relay. The directional indicator gets its power from the flasher relay and the signal for the hazard flashers runs back through the hazard switch before going to the lights.
I'd make sure to check power at the hazard switch, terminal 3 should have battery voltage when the ignition is turned on (power from fuse F6, 7.5 amp), and terminal 1 should have battery voltage at all times (power from fuse F9, 15 amp).
If you do have those correct voltages, I'd check power at the turn/hazard relay. At terminal 4 on the relay you should have battery voltage when the ignition key is turned on, and when the hazard switch is pressed but you should not have voltage at any other time.
The last thing I'd check is to see if you have a pulsing battery voltage signal at terminal 6 on the hazard switch when the hazard switch is depressed (I don't expect you'll have voltage at this terminal if the flashers aren't flashing but it needs to be checked for clues).
Good luck and let us know what you find.
2005 Ardent Red Elise, Gut Sport wing & splitter, custom diffuser, Sector111: DSBrace, gPan3, subStuffy2, Larini Sport muffler, decat pipe, Schroth Racing 5 pts, wheel studs, Team Dynamics 1.2 with Hoosier A6s, Koldflash 200 ECU flash, BOE rear clam hinge, BC Racing single adjustables, Hawk pads, SS Brake Lines, HID lights, custom tail and high mount brake light...and much more...