it's working... just not enough to prevent the light from coming on. Thing is, that switch that is associated with the Driver's seat is "closed" with someone in the seat and "Open" with noe one in the seat. So, you more than likely have a problem with the switch shunting to ground when someone gets in the car. You can get a new switch, disassemble clean and reassemble the current switch, or just unplug and remove the switch to resolve the issue.
Personally, I dislike all buzzy things in my car. So I unplugged the switch and got rid of it. DPO maneuver? Maybe, depending on how you look at it, but I don't plan on selling my B anytime soon and happen to like not having the buzzy thing.