2003 GMC Sierra 1500 Pickup Owner's Manual - Page 191

Passenger Air Bag Status Indicator If your vehicle is a regular cab pickup and this ever happens, don't let anyone whom the national government has identified as a member of a passenger air bag risk group sit in the right front passenger's position (for example, don't secure a rear-facing child restraint in your vehicle) until you have your vehicle serviced. If your vehicle is an extended cab pickup and this ever happens, don't let anyone whom the national government has identified as a member of the passenger air bag risk group sit in the right front passenger's position (for example, don't secure a rear-facing child restraint in your vehicle) until you have your vehicle serviced. If yourvehicle has the passenger sensing system your rearview mirror will have a passenger bag status air indicator. Passenger Air Bag Status Indicator - United States Passenger Air Bag Status Indicator - Canada When the ignition key is turned to RUN or START, the passenger air bag status indicator will light ON and OFF, or the symbol for on and off, for several seconds 3-36