airbags faults

hey just about three weeks ago my wife crashed my 2004 mazda6 2.0lD and what i did was to keep down the price of repair, i found a 2003 with the engine blown and swaped the front including the crash sensor under the bumper, the bags( only the drivers, the only one that deployed) and the seat belt. the airbag light is now flashing code 13. Does and one no what this is, or what i can do? is there any thing else i can swap from the spare car?