my airbag light wont turn off

If the airbag light has turned on, your vehicle has detected a malfunction that prohibits function of the airbags. There is a great possibility that if an accident were to occur, the airbags would not properly deploy as intended. My personal advice would be to bring your Legacy in to a repair facility and let them at least pull the codes, this will give you an idea of what is going on with the system and how to repair it.