Audio Input Jack
WARNING: This page is about a different car, the 2012 Ford Pickup, 2012 Ford F550 Super Duty, 2012 Ford F450 Super Duty, and 2012 Ford Cab & Chassis. However, it is still accessible from the selected car via links, so may be relevant.
The audio input jack is used to connect a portable MP3 device to the vehicle. When connected, the audio files from the MP3 player can be broadcast through the vehicle speakers.