the problem is logig board broken
its tinnny spring wire is water damaged and wire lusted and then disconnect
u need micro scope and soldering system if u wanna fix this problem
not easy fix by ordinary people
iphone 4s and 4 and 5, most located near by bottom side on logic board..
its blue coil tinny u need hot air blower for fix this..
i fixed this prob 2 times..
more details on youtube.. u find it out i don't know..
thks