The signal/four way flasher relay is mounted beside the fuse panel. The four way flasher is incorporated in the signal/wiper switch. Dust can accumulate in the four way flasher switch and then stop working, use a contact cleaner spray and the switch start working again.
If the turn signals on a car works but the hazard lights do not there may be a problem with the flasher switch. The flasher is located in the steering column, and a damaged unit can cause the lights to stop working.