My airbag light stays on all the time. I took the car to a shop, they read the codes and said it's a problem with the airbag in the pass seat. The guy said it seems like a short or a loose wire. I'm thinking maybe the car stereo shop left something loose when they did the audio install. Are there any common issues that will cause this light to stay on? What wires should I check? Worst case if I need to simply replace the airbag where do I get one and where can I find install instructions?

thanks guys