Thanks so much for your quick answer! I wouldn't have known or thought to disconnect the battery! The reason I'm removing the pretensioner is to send the whole seat belt assembly to a repair shop to have a new belt put in (I had to cut the belt to free my son who was stuck in it - it wasn't in an accident, he was just being stupid). After I've removed the pretensioner, is it OK to reconnect the battery so I can use the car, then disconnect again to reinstall the pretensioner when I get it back? It's going to be about a week or so.
You can use the car after removing the assembly but it will set a code in the airbag computer and the light will turn on. The drivers airbag will not be deployed in the event of an accident. (If it is the drivers pre tensioner you are removing)
You might check car-part.com to see if you can purchase a whole assembly from a yard in your area, it should be less money and a whole lot quicker than sending yours to have a new belt installed.
Let me know how I can help you with this
Hyundai Certified and 15+ years as an ASE Maser Tech