Haw do you resset the air bag light on 99 silverado?

The air bag light is on because there is a problem with the air bag system. As long as the air bag light is on the system is not working, so if you crash the bag won't work. The light won't go off until it's fixed. A scanning device can read the trouble codes to identify the problem. Many auto parts stores will read the codes for you for zip if you purchase the parts necessary to fix it from them.