It is an integrated part of the turn signal switch, common ly called a multifunction switch. To replace it the airbag must be removed and the steering wheel pulled. You will need to safely disconnect the airbag following the procedure for you car to prevent accidental discharge if the airbag. You will also need a steering wheel puller to remove the wheel from the ahaft. These can sometimes be rented from chain auto parts stores. Watch a youtube video (any car will do) before attempting this repair.