Chosen Solution
Regarding an iPhone 6s Plus, model A1634. The audio connection jack at the bottom of the phone (next to the charging port) does not return to the built in iPhone speaker when an external speaker connector is removed from the female connector port. As a result, the phone remains in “Headphone” mode at all times. What part do I need to replace?
It could be a software issue. You could try updating or just restoring the phone all together. If that doesn’t do anything I would replace the charging port and headphone jack ribbon cable. Here is a link: iPhone 6s Lightning Connector and Headphone Jack
