1. Click Safari in the Menu Bar at the top of the screen, then Preferences.
2. Click the Privacy tab.
3. Under Website use of location services, click Prompt for each website once each day or Prompt for each website one time only.
4. MacOS may now prompt you to enable Location Services. If it does, follow its instructions to enable Location Services for Safari.
5. Close the Privacy menu and refresh the page. Try using Current Location search again. If it works, great! If not, read on for more instructions.
6. Back in the Privacy dialog, Click Manage Website Data... and type yelp.com into the search bar.
7. Click the yelp.com entry and click Remove.
8. You're good to go! Close the Settings tab, reload this Yelp page, and try your search again.

If you're still having trouble, check out Safari's support page. You can also search near a city, place, or address instead.