The light would be on because you removed the old steering wheel and terminated the connection from that wheel and airbag and the steering column.The car then disables ALL the airbags (light on) as it thinks there is a fault or it has deployed.ie your airbags wont work while the light is on.Best way to sort it is to go see your regular mechanic and ask him to reset it for ya,chuck him a fiver and its jobe done,the proper way without bending pins into plugs (the DIY way,lol) If he cant reset it then there is def something wrong with the system/wiring,sensors etc,but its normally just the wheel change that did it :) hope that helps