the sensing diagnostic modual contains a little processor which monitors the operation of they system, it also checks the system every time you start the car up. if there is a fault in the system anywhere, the light will stay on, more than likely it will sensing diagnostic moduel, that's below the driver's seat, that's prety much all that can go wrong, all that's in a srsairbag system is a main wiring harnes, to a clock spring coil, (in the steering column) the inflator, and the diag modual.
if the airbag light comes on during normal driving conditions, take car to holden straight away. only holden have the tool for checking the srs airbag setup on the vr, ford have one for the ford's, and likewise. dont try to troubleshoot this yourself, youwill set the thing off. it's to save lives, you dont wanna mess with this
you can disable the system, but you wont have airbag's, and you wont have any insurance if in a crash.
by the way, srs airbag stands for supplemental restraint system, hence the srs acronym
cheers
garth
p.s. the airbag system is a completly free standing circuit, it has it's own little computer and everything, nothing is connected in anyway to the srs system. holden have a tool that can "scan" the circuit