Blinkers and Hazzards

I was looking for ideas on what could be causing my troubles.
My blinkers work fine, but my hazards when activated flash bright, but stay bright and wont flash. Ive tried different types of flasher units, LED and regular bulbs, however I cant seem to get them to work. Ive looked in the service manual but havent found the right answer and fix.
Again, just looking for ideas and things to try. Thanks!