Door Ajar Warning Chime
WARNING: This page is about a different car, the 2002 Ford Ranger. However, it is still accessible from the selected car via links, so may be relevant.
When any door is ajar and the ignition switch is in the RUN position, the door ajar instrument cluster lamp is activated and remains on until all doors are closed. A warning tone will sound once any time the key is in the ignition switch and any door is opened.