See also:

Operation
If the driver and/or front passenger have/ has not yet fastened the seatbelt(s) when the ignition switch is turned to the “ON” position, the seatbelt warning light(s) will flash for 6 seconds, ...

Gross Axle Weight (GAW) and Gross Axle Weight Rating (GAWR)
Gross Axle Weight The total weight applied to each axle (GAW) must never exceed the Gross Axle Weight Rating (GAWR). The front and rear GAWs can be adjusted by relocating passengers and luggage ...

Seatbelt warning light and chime
Refer to “Seatbelt warning light and chime”. ...