GMC 2003 Sonoma Owner's Manual page 84

If your vehicle has an automatic transmission it will be
programmed to have all the doors lock automatically
when the shift lever is moved out of PARK (P). All the
doors will unlock when the shift lever is moved back
into PARK (P).
On a manual transmission, all doors will lock when the
vehicle speed is greater than 15 mph (24 km/h).
The doors will unlock when the key is removed from the
ignition.
The following instructions detail how to program your
door locks. Choose one of the programming options
before entering the programming mode.
To enter the program mode, do the following:
1. Begin with the ignition in OFF. Then pull the turn
signaVmultifunction lever all the way toward you
and hold it while you perform the next step.
2. Turn your key to RUN and OFF twice. Then, with
the key in OFF, release the turn signaVmultifunction
lever. Once you do this, you will hear the lock
switch lock and unlock.
3. You are now ready to program the automatic door
locks. Select one of the previous four programming
options and follow the instructions. You will have
30 seconds to begin programming. If you exceed
the 30 second limit, the locks will automatically lock
and unlock to indicate you have left the program
mode. If this occurs, repeat the procedure beginning
with Step 1. You can exit the program mode any
time by turning the ignition to RUN. The locks
will automatically lock and unlock to indicate you
are leaving the program mode. If the IocWunlock
switches are not pressed while in the programming
mode, the auto IocWunlock setting will not be
modified.
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