The Airbag Not Activated light turns on for the passenger side whenever there's a passenger sitting in the front. The same thing happens with the seatbelt light on the passenger side.
Many cars today have passenger detection systems so that in the event of a crash only airbags that are needed deploy. Air bags are expensive to replace, so if there isn’t anyone sitting in the passenger seat they do not want the passenger airbag to go off during a crash. Your question is telling me that there is a fault in this system. Typically there is a sensor in the seat cushion that can detect when someone is sitting in the seat. It is very common for these sensors to go bad due to normal wear and tear from people sitting in the seat. I would ask for help from a mechanic, such as one from YourMechanic, to take a look at your airbag systems and diagnose what is causing your problem.
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