Chosen Solution
I replaced an iPhone 7 screen for a customer yesterday, and I tested the home button haptics which worked fine. So I assumed touch ID would work as well (it’s the original home button of course). I’ve never experienced this before. In the past it’s always worked or it hasn’t - or maybe sometimes the touch ID worked but the haptics didn’t which usually turned out to be a bad flex on the replacement screen. This time, it’s a little weird. Home button works perfectly fine, but touch ID doesn’t. I’ve had her hard restart the phone to no avail. Funny thing is, the phone seems to think that touch ID works. When adding a new fingerprint, it doesn’t fail at the screen where you register the fingerprint, it just doesn’t register anything. She’s coming by later today for me to take a look at it. I’ve got a few ideas on what to look at, but I’m interested in seeing if anyone else has had a similar issue and may have some troubleshooting ideas. Here’s what I’m going to try: Reconnecting all flex cablesLoosening the tri-point screw right on the home button. I’ve read some people had issues when it was tightened too hard.Try original screen to rule out bad replacementTry DFU restore Anything else I should have in the toolbox?
That’s a good list of things to try/verify. I would add a close inspection, preferably with magnification, of the Home Button flex cable. Usually TouchID fails completely, not partially so perhaps there is a tiny tear in the flex.
There is not much you can do for this problem—in my experience this will almost always be a microtear in the cable which is very common. You can rule out the screen, but this is most likely going to require a trip to Apple or living without fingerprint sensor function.
