GMC Sierra Denali Owner's Manual page 77

The passenger sensing system is designed to turn off
the passenger's frontal air bag when a rear facing infant
seat, a forward-facing child restraint or a booster seat
is detected. If the child restraint has been installed
and the on indicator is lit, turn the vehicle off, remove
the child restraint from the vehicle and reinstall the
restraint following the child restraint manufacturer's
directions and refer to Securing a Child Restraint in the
Right Front Seat Position on page 1-50 of this manual.
If after reinstalling the child restraint and restarting
the vehicle, the on indicator is still lit, secure the child in
the child restraint in a rear seat position in the vehicle
and check with your dealer.
The passenger sensing system is designed to enable
(may inflate) the right front passenger's frontal air
bag anytime the system senses that a person of adult
size is sitting properly in the right front passenger's seat.
When the passenger sensing system has allowed the
air bag to be enabled, the on indicator will light and stay
lit to remind you that the air bag is active.
If a person of adult-size is sitting in the right front
passenger's seat, but the off indicator is lit, it could be
because that person isn't sitting properly in the seat
or the air bag off switch is in the off position. If this
happens and the switch is in the proper position, turn
the vehicle off and ask the person to place the seatback
in the full upright position, then sit upright in the seat,
centered on the seat cushion, with the person's
legs comfortably extended. Restart the vehicle and have
the person remain in this position for about two
minutes. This will allow the system to detect that person
and then enable the passenger's air bag.
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