Chosen Solution
I changed the battery in my iPhone 7 with an IFIXIT kit yesterday. The repair went well except that the touch ID doesn’t register fingerprints anymore. The home button functions normally otherwise. I’ve removed and attached the screen several times now and can’t see any damage to the ribbon cables. I also disconnected and reconnected the battery. Are there any suggestions for fixing the touch ID? I saw one similar question where the person bought a new screen and was successful. Is that the first or main solution, or are there any tests or other things to try? Thank you for any suggestions. John
If you were just changing the battery, and you didn’t unscrew the home button itself (which is very susceptible to nano-tears) then the most likely reason you lost Touch ID is from stress/rough handling of the flex on the screen that is the conduit for home button/touch id data. It is easy to tear or stretch that flex.
To rule that out, see if a new screen will solve. That would be your next step.
