GMC 2006 Sierra 1500 Pickup Owner's Manual page 105

The following instructions tell you how to change the
automatic door lock mode (automatic transmission only).
Choose one of the two programming options listed above
before entering the program mode. To enter the program
mode, do the following:
1. Begin with the ignition off. Then pull the turn
signal/multifunction lever toward you and hold
it there while you perform the next step.
2. Turn the key to RUN then back to LOCK twice.
Then, with the key in LOCK, release the turn
signal/multifunction lever. Once you do this, the
doors will lock and unlock, the horn will chirp twice,
and a 30-second timer will begin. You are now ready
to program the automatic door lock feature.
3. Press the door lock switch once. You will hear either
one or two chimes. The number of chimes tells you
which lock mode is currently selected. Continue to
press the door lock switch until the number of chimes
that you hear matches the number of the mode that
you want. If you take longer than 30 seconds, the
locks will automatically lock and unlock and the horn
will chirp twice to indicate that you have left the
program mode. If this occurs, you can repeat the
procedure beginning with Step 1 to re-enter the
programming mode.
You can exit the program mode any time by turning the
ignition to RUN (the doors will automatically lock and
unlock and the horn will chirp twice to indicate that you
are leaving the program mode). If the lock/unlock
switches are not pressed while in the programming
mode, the current automatic settings will not be modified.
See your dealer for more information.
Programmable Unlocking Feature
The following is the list of available programming
options:
Mode 1: Driver's door unlocks when the transmission
is shifted into PARK (P), for automatic transmission
vehicles only.
Mode 2: All doors unlock when the transmission is
shifted into PARK (P), for automatic transmission
vehicles only. This is the mode that is pre-programmed
in the factory for your vehicle.
Mode 3: All doors unlock when the key is removed from
the ignition. This is the mode that is pre-programmed in
the factory for manual transmission vehicles.
Mode 4: No automatic door unlock.
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