Did you replace with an aftermarket or an original setup? If aftermarket then there should be a by pass for the airbag. If original you will need to reset the airbag light via the houselight sequence. Leave driver door open, put key in ignition and switched to the ON position without starting, press the houselight door button 7-10 times and then remove the key and then close the door and start the car. The air bag light should be reset.
Also if you removed the wheel and in error spun the spiral cable unit and then replaced it can cause the spiral cable to snap and you will lose your horn and air bag functionality. When you're installing the new wheel I suggest you either tape the spiral cable unit stationary or failing that you will need to figure out the amount of revolutions from left to right and then divide it by two to find the center point where the wheel should then be mounted and install the wheel at that point ensuring that the front wheels are aligned properly. Hope it helps somewhat.