I don't know. In
viewtopic.php?t=20246" onclick="window.open(this.href);return false; GMJAP and prathman posted the procedure for later auto models, might be worth trying it to see if it works. Sounds like you want mode 2. They said
1) Car in park
2) close all doors
3) dome light switch set to "door"
4) key in and turn to ON (do not start) - leave at ON
5) immediately press and hold driver's door lock switch in LOCK for 5-6 seconds.
6) Dome light flashes # times to indicate mode
remove key & repeat 4-6 to change mode.
Mode 1: All doors and liftgate lock when the shift lever
is moved out of PARK (P) with the ignition on and all
doors and liftgate closed. There is no automatic
door unlocking.
Mode 2: No automatic door locking or unlocking.
Mode 3: All doors and liftgate lock when the shift lever
is moved out of PARK (P) with the ignition on and all
doors and liftgate closed. All doors and liftgate
unlock when the shift lever is moved to PARK (P) with
the ignition on.
Mode 4: All doors and liftgate lock when the shift lever
is moved out of PARK (P) with the ignition on and all
doors and liftgate closed. All doors and liftgate
unlock when the ignition switch is turned from ON to
ACC or to LOCK. Mode 4 is the factory setting.