This lamp illuminates and an audible warning will sound if the driver seatbelt has not been fastened when the vehicle's ignition is turned on.
Conditions of operation

If  Then 
The driver seatbelt is not buckled before the ignition switch is turned to the on position...  The seatbelt warning light illuminates and the warning chime sounds for a few seconds. 
The driver seatbelt is buckled while the indicator light is illuminated and the warning chime is sounding...  The seatbelt warning light and warning chime turn off. 
The driver seatbelt is buckled before the ignition switch is turned to the on position...  The seatbelt warning light and indicator chime remain off.