airgbag error, four doors and trunk open, brake light on 407 peugeot

It sounds like perhaps a fuse has blown and will need to be replaced before resetting anything and if all the fuses are ok check all the globe's starting with the 4 indicator globe's (sometimes the main computer is affected by an unsteady electric current and this causes havoc with the entire electric system) I hope this solves your problem , please post an update, informing if your problem was resolved.