Rear Door Security Locks
Your vehicle may have this feature. You can lock the rear doors so they cannot be opened from the inside by passengers. To use one of these locks do the following:
1. Open one of the rear doors. You will find a security lock lever located on the inside edge of each rear door.

2. Move the lever down to engage the security lock.
Move the lever up to disengage the security lock.
The rear doors of your vehicle cannot be opened from the inside while this feature is in use. If you want to open the rear door while the security lock is on, unlock the door and open the door from the outside.
See also:
Insuring Your Vehicle
Protect your investment in your GM vehicle with
comprehensive and collision insurance coverage. There
are significant differences in the quality of coverage
afforded by various insurance policy ...
Delayed Entry Lighting
The interior lamps will turn on if you open the door when
it is dark enough outside. When you close the door with
the ignition off, the interior lamps will stay on for up to
25 seconds or until ...
Sheet Metal Damage
If the vehicle is damaged and requires sheet metal repair or replacement, make sure the body repair shop applies anti-corrosion material to parts repaired or replaced to restore corrosion protection.
...
