Disconnect the battery and wait 10 mins after you have taken the seat retaining bolts out from the base, you will need power to move the seats back and forwards to get on the bolts. After a 10 min wait you will be ok to disconnect the underseat wiring, if the battery is left connected and the ignition turns on it will set the airbag light which will have to be cleared with a code reader. Always safer to disconnect the battery to avoid triggering the airbag light.