How to troubleshoot the lightning connector?

i’d seen this issue before, when a phone simply won’t juice up.

if you can get your hands on a USB Ammeter (<$10 on amazon or ebay) you can see if the phone is actually drawing current through the usb/lightning cable.

the next step is to try a new battery. i’ve had several phones come across my bench that were so discharged, even when plugged in to a 2.1A (iapd) a/c brick, you don’t even get the empty battery with the thin red line on the screen. put a different battery with some charge and it powered right up. at that point, it’s 50/50 if you can actually get the old battery over the hump to take a charge. sometimes putting that battery into a different phone worked, sometimes it didn’t.

i’ve read articles about a chip in the motherboard and/or a chip in the battery that gets to a point where it just can’t charge the battery. the good news is that batteries (and the tools to open your phone) can be found here on ifixt, ebay, amazon, injuredgadgets, etc. and are not that expensive. ebay will likely be the cheapest, but unless you’re an experienced ebay shopper and phone geek, you’re probably better off paying more and buying from a place that will give some level of support.

do take advantage of the guides and resources here on ifixt to give you what you need to know about how to do the battery replacement