Delayed Locking Operation
WARNING: This page does not describe the selected car, but rather 8 other vehicles, including the 2008 GMC Yukon XL, 2008 GMC Yukon, 2008 Chevrolet Tahoe, 2008 Chevrolet Suburban, and 2008 Chevrolet Avalanche. However, it is still accessible from the selected car via links, so may be relevant.
With any door open and a door lock switch is activated in the lock position, the driver door switch (DDS), passenger door switch (PDS) and the body control module (BCM) will go into a lock pending state. The BCM will also give 3 audible chimes. When the door is closed, the DDS, PDS and the BCM will lock the doors after approximately 5 seconds. This feature can be overridden by activating the door lock switch a second time and the doors will lock even with a door open.