Chosen Solution

I just fixes an iPhone 5s which wasn’ charging and didn’t respons to DFU reset. Turns out, a new battery did the trick. But here is whist pusseled me: The guy who sold it swore that it wasn’t water damaged, The water indikator by the ear speaker and sim tray was bright white, but the one by the battery was red. Seems impossible. Can anyone explain? Bjop

It is possible, water didn’t go all the way trough the iPhone…often situation in servicing business. If everything else is ok, don’t bother, carry on with usage…

It is most likely not water damage to the entire logic board. Probably a small amount of water from rain, or another source got into the phone. Since the water damage indicator near the battery was red, the water probably got into battery connector. This would short the pins in the connector causing rapid power cycling ultimately killing the battery. Even though replacing the battery, in this case, would fix the problem, I would recommend inspecting the logic board for any other corrosion before continuing use. Doing this will ensure you don’t have any issues further down the road.