The Lightning Connector 4th PIN blackening can cause intermittent or no charging. To resolve this, the first step is to try cleaning the lightning connector with alcohol. In severe cases, you may need to scrape the 4th pin on both sides of the Lightning Connector using something sharp or slightly abrasive, removing the blacked deposits on the connector. This may not always resolve the issue.
Severe blackening is caused by water or extremely high humidity being present on the cable or in the iPhone port when plugging it in. This can happen if the phone has gotten wet, been in a humid room such as the while a shower is running, or from outside rain or high humidity in some climates. You may also see minor blackening that can be caused by having the cable plugged into power when plugging it into your device. It is similar to the spark you see when plugging in a small appliance, such as a hair dryer, with the appliance already turned on. Because this involves improper usage and/or water damage, it is not an item covered by warranty. However, please contact us with your receipt and photo of the cable and we can offer a discounted replacement.
In the future. You can prevent this "blackening" of the 4th PIN by following simple procedures. Ensure your cable and phone are completely dry and plug the Lightning Connector into your phone before you connect the cable to power.