Many iPhone users claimed, after the iPhone 6S screen replaced, the 3D touch no work any more. Sometimes, they even can't use the Touch ID. It is a headach problem for all repair shops. Now, we explain why this happen, and how to fix the problem. As we know, there is a Touch ID built-in to the iPhone 6S mainboard and home button, the code in home button must match the code in mainboard, then the touch ID can work. If the home button is replaced, then the touch ID is out of work. So mostly, the problem happened on the home button, but not on replaced screen. what is more, there is a home connecting flex cable on iPhone 6S home button, which connect the home button to mainboard. It control the touch ID function. If the flex doesn't connect to mainboard well, the touch ID will also not work. The 3D touch function has nothing to do with screens. Mostly, after iPhone LCD replaced, the 3D touch continue to work. If there is no 3D touch function after iPhone 6S screen replacement, it probably because the flex connection is not well.