Luxury Keyless Entry System: Unlocking
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 UNLOCK button on the transmitter once to unlock the driver's side door. Press the UNLOCK button twice within a half a second, and no later than three seconds time to unlock the remaining doors.