Inertia reel control electronics

The automatic reel control electronics are supplied with voltage by the distribution box in the junction box from terminal 30g onwards.

A sensor is integrated in the automatic reel control electronics. The sensor detects the longitudinal acceleration, the lateral acceleration and a rollover.

If specific acceleration values are exceeded, the control electronics activates directly the two lifting magnets (on the driver's side and the passenger side). When doing this, the two lifting magnets are de-energized. In this case, the seat belt locking reel is active.

Fig 1: Identifying Inertia Reel Control Electronics Components

Courtesy of BMW OF NORTH AMERICA, INC.