Standard Keyless Entry System: Locking
WARNING: This page does not describe the selected car, but rather 7 other vehicles, including the 1999 GMC Yukon, 1999 GMC Suburban, 1999 GMC Pickup, 1999 Chevrolet Tahoe, and 1999 Chevrolet Suburban. However, it is still accessible from the selected car via links, so may be relevant.
Press the LOCK button on the transmitter to lock all of the vehicles doors at once. Press the LOCK button a second time to verify that the doors are locked. A horn will sound to verify that the doors are locked.