Chevrolet 2003 Silverado 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 (1 3 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.
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