I have 2010 Rogue and I just installed my Sirius Radio in the car. To do this I did remove the factory radio to install a direct fm connection to the back of the radio. I also wired the power in to lighter power to leave the socket free for my gps unit. Any how when I was done I had a flashing airbag light on. A little research and I found that when I removed the hvac control panel that has the passengers airbag light in it and turned the key on to test things while this was disconnected most likely triggered the light. I tried the above and it did not work, maybe timing I don't know. Any how I found these directions that are a little easier to follow but more or less the same and it worked.
Try This, I got this from ClubArmada.com It worked for me.
Since some of you guys here are new owners I thought I'd save you a trip to the dealer once you start modifing your armada's. I'm not sure what set's it off (other than pulling things apart) but at some point you will likely end up with a flashing airbag sensor light. Here is how to reset it yourself.
1. Turn the key from off to on.
2. Watch the airbag light closely. It will stay on for a few secs. and then as soon as it blinks off (the start of the flashing), turn the key off instantly.
3. Count to 5 (1 Mississippi, 2 Mississippi . . . .)
4. Repeat steps 1-3 two more times until you have done the cycle three times.
5. Now turn the key on and watch the light. It will start blinking in a different, slower manner. This is diagnostic mode. You can watch this for a little while, no hurry.
6. Now turn the key off again, Count to 5 like in step 3 again, and turn back on. If the procedure worked, the airbag light will not be flashing.
Hope this helps.