Welcome to iRV2.
The emergency ( 4 way ) flasher system has it's own fuse and flasher , so the first thing to check would be the chassis fuse box. The turn signal flasher and the emergency flasher are usually very close to each other , so if you can track the signal flasher by the clicking then you should be able to see the other flasher. Flasher assemblies are common and any auto parts store will have one to match yours ; if that's the problem $10>12 for a HD unit.
If you could add chassis info to your post ( gas ? diesel? Chevy ? Ford ? ) maybe another member can give you an exact location.
99DSDP 3884, Freightliner, XC, CAT 3126B, 300 HP /ALLISON 3060
2000 Caravan toad, Remco & Blue Ox.