Safety Belt Reminders - GMC 2010 Sierra 1500 Crew Cab Owner's Manual

When the engine is started, a chime sounds for several
seconds to remind a driver to fasten the safety belt,
unless the driver safety belt is already buckled.
This chime and light sequence are repeated if the driver
remains unbuckled and the vehicle is in motion. If the
driver safety belt is already buckled, neither the chime
nor the light comes on.
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The safety belt light
flashes for several
seconds, then comes on
solid for several more.
For vehicles equipped with the passenger safety belt
reminder light, several seconds after the engine is
started, a chime sounds for several seconds to remind
the front passenger to buckle their safety belt. The
passenger safety belt light, located on the overhead
console, comes on and stays on for several seconds,
flashes for several more seconds and then comes on
solid for several more.
If the passenger safety belt is buckled, neither the
chime nor the light comes on.
The front passenger safety belt warning light and chime
may turn on if an object is put on the seat such as a
briefcase, handbag, grocery bag, laptop or other
electronic device. To turn off the warning light and or
chime, remove the object from the seat or buckle the
safety belt.
This chime and light
sequence is repeated if
the passenger remains
unbuckled and the vehicle
is in motion.