Replaced several iPhone 7 & 7plus screens, home button will not function at all! They all worked before I changed them. Even tried a new home button, still have to use assistive touch. What am I doing wrong?
First, the home button of the 7 and 8 series are irreplaceable. The serial of the TID is tied to the motherboard.
Second, the only thing is repairable with said home buttons is the force touch function. Meaning, if it reads your fingerprint but no action when you press on the home button. It is done via replacing the IC (Turtle) on the flex cable.
You probably either torn the flex cable, applied too much heat to the button itself or stretched the cable too much that the components on it no longer making contact due to broken solder joints.
Your option is to try with a known good screen or if it still doesn’t work, buy a universal home button, but you won’t have TID function that way.