GMC Yukon XL 2013 Owner's Manual page 43

Safety Locks
The vehicle has rear door security
locks to prevent passengers from
opening the rear doors from the
inside.
Open the rear doors to access the
security locks on the inside edge of
each door.
To set the locks, insert a key into
the slot and turn it to the horizontal
position. The door can only be
opened from the outside with the
door unlocked. To return the door to
normal operation, turn the slot to the
vertical position.
Keys, Doors, and Windows
Doors
Liftgate
Exhaust gases can enter the
vehicle if it is driven with the
liftgate or trunk/hatch open,
or with any objects that pass
through the seal between the
body and the trunk/hatch or
liftgate. Engine exhaust contains
carbon monoxide (CO) which
cannot be seen or smelled. It can
cause unconsciousness and even
death.
If the vehicle must be driven with
the liftgate or trunk/hatch open:
Close all of the windows.
Fully open the air outlets on
or under the instrument
panel.
2-9
WARNING
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