Sync 4 GPS issue

What was the vehicle equipped with originally? Sync version?

If you see no satellites in the diagnostic menu then there is an issue with the GPS antenna, most likely. You can troubleshoot this using this guide, it’s the same as Sync 3.

GPS Hardware Test: The Compass/Navigation is Inoperative or Does Not Operate Correctly. (No GPS) - Ford / Guides - CyanLabs Official Community