Child Protection Lock
WARNING: This page is about a different car, the 2003 Dodge Intrepid, 2003 Chrysler Intrepid, 2003 Chrysler Concorde, and 2003 Chrysler 300M. However, it is still accessible from the selected car via links, so may be relevant.
The lock when engaged, will disable the inside door handle from opening the door. The lock is part of the lever that is located on the rearward inside edge of the door.