this question came up once before, it was very helpful to me . I have berlingo and was told that the airbag is some how connected to the inertia seatbelt and that the connector for it is under the drivers seat after checking with the ign off found said connector and just pushed it together, turned the ign on and it was solved. My son on his car had the same problem but he disconnected his and reconnected it and we solved that the same way as well. whether it solves it for you, but worth a try. hope so good luck.