GMC 2008 Envoy - Manual (Page 85)

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.
3. Close the door.
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.
Lockout Protection
This feature stops the power door locks from locking
when the key is in the ignition and a door is open
to protect you from locking your key in the vehicle.
If the power lock switch is pressed when a door is open
and the key is in the ignition, all the doors will lock
and then the driver’s door will unlock.
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