Is the "airbag light on" light supposed to stay lit when there's a passenger in the seat or should it go out after a short time? I tried to find the answer in the manual but didn't have any luck....

 

there are sensors in the car that classify who ever is in the passenger seat so that the airbags only go off when they need to. the light stays on to indicate that the car knows a person is in the seat. kinda cool actually

 

The answer is in the manual. It uses a weight sensor on the seat, the bag may turn on if you leave something heavy on the seat also.