You probably unplugged your passenger airbag light. Some cars you can't even unplug it, some you can, but can't turn the ignition on with it unplugged. Make sure it is plugged in, and disconnect your battery cables (both) and leave them disconnected for about 5-10 minutes. Then touch the cables together (still not connected to the battery!!) This will drain any surface charge in any component in the car. Leave them together for a few more minutes, and then seperate them and reconnect the battery. This will clear the airbag lights in many cars. Make sure if your radio has a code that you know it before doing this, since you will be removing power from it by disconnecting the battery.
