For the last few months I have been suffering from a bout of the Airbag Warning Light coming on, going off etc, etc. This seemed to occur either after hitting a bump or on start-up. On one occasion my specialist dealer re-set the light only for it to come on again after a few weeks.
So I decided to investigate.
Their is a box under each front seat that can be slid forward after releasing a "plug-in" catch on the side of the box, the connector can then be parted and checked; mine were OK on both sides.
On the saloon there is also a box in the boot; this is located on the bracket supporting the boot light. It was difficult to access - mind the hot bulb

and to be honest all I did was to fiddle with the wires. Anyway the warning light went out and is still out after nearly a week later. Having said that I know what will happen tomorrow
Hope that is of use, at least it re-set without a trip to the dealer, it beats running round without the airbags working.
Rob