Front passenger seat occupancy sensors and seat belt latch sockets are common faults and both easily fixed. Airbag light activations give you strong bargaining power in purchasing a used BMW. I got $3000 off for an airbag light activation that turned out to be a bad front passenger seat sensor. I built a little circuit which fools the airbag module into thinking the front seat is always occupied for less than $1 and reset the light which has stayed off ever since (the circuit is described in this link
4shared.com - document sharing - download Seat Occupancy Sensor ByPass.pdf ). The only downside is that both airbags will deploy in the event of a crash. A replacement sensor was about $250 and I will instal it myself when I get the motivation.
