Front Air Bag Sensor Control problems of the 2007 Nissan Altima Hybrid

2007 Nissan Altima Hybrid. Passenger airbag sensor light illuminates,indicating airbag is off, whenever my wife (5ft 3in , 118lbs) is in the front passenger seat. Have taken it to dealer who tell me that sensor is functioning "according to Nissan's specifications. " would like some direction on what to do next.

Passenger airbag is deactivated at random times (sometimes for entire 20+ minute trips) regardless of the weight of passenger (all more than 100 pounds, some more than 200 pounds). I believe the sensor is defective. Nissan has recalled several vehicles of my model year, 2007, and even my model, Altima Hybrid, has a recall, but my VIN is not included. I believe that my car has the defect that led to the recall, and even though I've taken it to the dealer at least thrice, they don't do anything other than run it on the computer for error codes. God forbid we have an accident and the airbag does not inflate. This has been happening since the car was new and is ongoing. Thankfully we have not needed the airbag.