I've had the same old problem with the passenger occupancy sensor that it seems like everyone else has had too. Instead of paying 800 bucks to have the sensor mat replace, I purchased this: BMW Seat Occupancy Sensor Emulator
I would have purchased one of the better "plug and play" ones if I had seen them first.
Anyone have any experience with this one? It's for a 2006 325i. I'm not even sure how to wire it up. Also, it says something about buckling the seatbelt all the time?!?