I was told by Apple Tech that even certain cases can prevent GPS from working.
I had brand new iPhone 8, transferred all my apps and after about two weeks, GPS stopped working. Apple Genius did hardware diagnostic- all good. Checked w/ ATT, not a network issue.
Called AppleCare, excellent tech mirrored my screen, had me check all the location and Bluetooth stuff, all correctly set; tech then had me try:
1- turn off/ on my Apple Watch
2- reset network settings
3- reset all settings
After none of these fixed the gps:
4- did a full restore, set up as a NEW phone. Didn’t bring in any third party apps. GPS worked fine, in WAZE, Apple Maps, Google maps..
5- now bringing back a few third party apps at a time, still ok. Good opportunity to clean out the unused apps.
***After a few days, I’m thinking it was my Jigsaw Puzzle app, or an older installed but never played game like Peppers, or Angry Shark. Something w/ a lot of moving parts, maybe? So I plan to bite the bullet, live w/o games for awhile and see if it continues to work fine.
A full restore to new phone will prevent your phone from inheriting any bad apps.