For 1990-2009 cars

When the key is turned to RUN or START, a chime will come on for several seconds to remind people to fasten their safety belts, unless the driver's safety belt is already buckled.

The safety belt light will also come on and stay on for several seconds, then it will flash for several more.

This chime and light will be repeated if the driver remains unbuckled and the vehicle is in motion.

If the driver's belt is already buckled, neither the chime nor the light will come on.