2003 GMC Sierra 1500 Pickup Owner's Manual - Page 210

Automatic Locking Press the personalization button until AUTOMATIC LOCKING appears in the display. To select your personalization for automatic locking, press the select button while AUTOMATIC LOCKING is displayed on the DIC. Pressing the select button will scroll through the following choices: LOCK DOORS OUT OF PARK (default): The doors will lock when the vehicle is shifted out of PARK (P). LOCK DOORS MANUALLY: The doors will not be locked automatically. LOCK DOORS WITH SPEED: The doors will lock when the vehicle speed is above 8 mph (13 km/h) for three seconds. Choose one of the three options and press the personalization button while it is displayed on the DIC to select it and move on to the next feature. For more information on automatic door locks see Programmable Automatic Doors Locks. Automatic Unlocking Press the personalization button until AUTOMATIC UNLOCKING appears in the display. To select your personalization for automatic unlocking, press the select button while AUTOMATIC UNLOCKING is displayed on the DIC. Pressing the select button will scroll through the following choices: UNLOCK ALL IN PARK (default): All of the doors will unlock when the vehicle is shifted into PARK (P). UNLOCK ALL AT KEY OUT: All of the doors will unlock when the key is taken out of the ignition. UNLOCK DOORS MANUALLY: The doors will not be unlocked automatically. UNLOCK DRIVER IN PARK: The driver's door will be unlocked when the vehicle is shifted in PARK (P). Choose one of the four options and press the personalization button while it is displayed on the DIC to select it and move on to the next feature. For more information on automatic door locks see Programmable Automatic Door Locks. 3-55