Chosen Solution
So I just replaced the screen of an iPhone 5s. During the repair everything went good, no weird things. I did everything step by step as I always do. After closing the phone I connected it to a power cable, nothing happened. No charging sign nothing. It also doesn’t turns on. So I opened the phone again and checkt everything, it all looks good. Closed the phone again and as espected, nothing happened. I need help, I don’t know what could cause this problem. Update (08/16/2016) Found it, the battery is dead. Thank you all!
Battery/charging flex/logic board are the possible faulty parts. If the screen is faulty and you connect it to a mac, iTunes should start. If it doesn’t happen, then one or more of the internal parts are faulty.
