Disconnect your battery then remove the airbag to see if you can find the missing screw. There is only 2 screws that hold the bag in. If you're looking at the back of the wheel you'll see one of the 2 holes on each side is more centered. Those are the ones with the screw. It's a torx head screw (T-25 if I remember correctly). Simply unscrew the remaining screw and the bag will fall right out. YOu want to be sure that that lost screw is not in there. You run the possibility of grounding the horn (causing it to blow)at the very least. You also run the risk of damaging more important wires. With the bag removed you'll see 2 metal tabs which are the horn contacts. Look behind them because the screws tend to get caught between the backside of the horn tabs and sterring wheel hub. If you can't find it I would recommend getting another and secureing the bag correctly. You don't want that airbag to be loose should it go off in an accident. That thing will become rocket!
I find a loose airbag to be common on some of these cars for some reason. If you can't find a replacement screw let me know and I can mail one to you. I have tons of them lying around.
