2003 GMC Yukon Owner's Manual - Page 194

The safety belt light will also come on and stay on for several seconds, then it will flash for several more. This light will come on when you start your vehicle, and it will flash for a few seconds. Then the light should go out. This means the system is ready. If the air bag readiness light stays on after you start the vehicle or comes on when you are driving, your air bag system may not work properly. Have your vehicle serviced right away. If the driver's belt is already buckled, neither the chime nor the light will come on. Air Bag Readiness Light There is an air bag readiness light on the instrument panel cluster, which shows the air bag symbol. The system checks the air bag's electrical system for malfunctions. The light tells you if there is an electrical problem. The system check includes the air bag sensors, the air bag modules, the passenger sensing system (if equipped), the wiring and the crash sensing and diagnostic module. For more information on the air bag system, see Air Bag Systems on page 1-70. Passenger Air Bag Status Indicator If your vehicle has the passenger sensing system your rearview mirror will have a passenger air bag status indicator. 3-40