Cutting the connectors off and soldering isn't necessary and makes life difficult if for any reason you have to remove the seats.
Usually all that's needed is to unplug and plug them in s few times, did that today on a customer's car and the airbag light went out
Makes sure also that the connectors are secured properly to the seat frame so they don't get caught by passengers feet or drag on the carpet which also causes problems.
Russ