Im assuming you have checked all of the bulbs ? even if they light up sometimes the filiments can cross and short the flasher out ..
if all the bulbs check out you may have a bad socket , that year I believe had some issues with burned sockets that would loose connection , the issue required replacment of the light socket assemblys ( the dealer could tell you if your car was effected by that problem) otherwise you may simply have a bad flasher assembly ..but you will need to check all .