The seat occupancy sensor light on your BMW is tied in to the SRS system (the airbag and supplemental restraint system). When there is a problem with the airbag system on your BMW, the SRS light will illuminate on your dash. Since the airbag/SRS system is quite complicated, you should have a professional mechanic service the system itself. Once this is done, you can reset the sensor light using BMW's proprietary reset tool.
Open the fuse panel cover on your BMW. Pull the fuse panel cover down and locate the large circular on board diagnostic port (OBD port) on the fuse panel.
Plug the electrical connector from the reset tool into the fuse panel port.
Turn the ignition key to the "II" position and wait for the sensor light to shut off.
