Chosen Solution
I was just about to unlock my iPhone 6s, when I placed my finger on the home button I felt something hot (but the home button works well). I unlocked my phone then the home button has cooled down. I found out that my touch id has been turned off and my fingerprints are all gone then I tried turning it on again but it didn’t work. I reboot and restart my phone, I get notification that the phone is unable to activate touch id. The add fingerprint is disable on the settings. I found out that when my phone is locked, it will heat up but then when I unlock it, it will cool down after a few secs. It doesn’t work with “RESTORE” option.
Internal short. Go to Apple for repair. It is basically impossible to repair this by anyone else.
Sounds like a short in the button. Could be caused by moisture. I would advice you to open the phone up and change the button, in the process you can look for the LDI’s and see if they have change colour to red, indicating liquid damage. Just note, that by changing the button, TouchID functionality is gone for ever.
