Normally, when you use a pair of headphones in the iPhone jack, a sensor inside the jack detects when the headphones are removed, and it turns off the headphone mode. Occasionally, grit may become lodged in the jack and interfere with the operation of the jack sensor. If you find that your headphone mode doesn’t turn off on your iPhone or if you can’t hear sound through the iPhone speakers, try a few troubleshooting tricks to get your phone working properly again. Warnings Writer Bio
