It sounds like you have a weight sensor on the passenger's seat that can be off but to be sure lets run the codes to see if anything comes up here is a guide to help you.
A light is not turning on, but a light is turning on to tell you something? All cars have a red "Air Bag" light on the dash. That must turn on for about six seconds when you turn on the ignition switch. That's for a visual bulb check, and the computer is performing self-tests. If that light turns off after those self-tests, the system is working and all of the air bags will deploy in a crash, under the right conditions. It's when that light turns on while you're driving that a problem has been detected by the computer, it turns the system off so the bags will not deploy in a crash, it sets a diagnostic fault code in the computer, and it turns the light on to tell you.
Totally separate from that is a yellow "Passenger Air Bag Off" information light. The passenger airbag has to be manually turned off, usually with a key, to deactivate it. Only the passenger airbag will not deploy in a crash when that yellow light is on. I've never seen that switch and yellow light in a car.
If the sensor is bad here is how you change (below)
Please let us know if you need anything else to get the problem fixed.
Images (Click to enlarge)
Tuesday, January 2nd, 2018 AT 3:18 PM