2008 GMC Sierra 1500 Pickup Owner's Manual - Page 172

Safety Belt Reminders Safety Belt Reminder Light When the engine is started, a chime will sound for several seconds to remind people to buckle their safety belts. The driver safety belt light will also come on and stay on for several seconds, then it will flash for several more. You should buckle your seat belt. This chime and light will be repeated if the driver remains unbuckled and the vehicle is in motion. Passenger Safety Belt Reminder Light Several seconds after the engine is started, a chime will sound for several seconds to remind the front passenger to buckle their safety belt. This would only occur if the passenger airbag is enabled. See Passenger Sensing System on page 1-63 for more information. The passenger safety belt light will also come on and stay on for several seconds, then it will flash for several more. This chime and light are repeated if the passenger remains unbuckled and the vehicle is in motion. See DIC Warnings and Messages on page 3-59 for more information on driver and passenger safety belt reminders. If the driver's belt is buckled, neither the chime nor the light will come on. See Passenger Sensing System on page 1-63 for more information. If the passenger's safety belt is buckled, neither the chime nor the light will come on. 3-36