Inertia Switch

In the event of an impact registering at greater than 14G the Inertia Switch goes open. This open removes the voltage from X254 pin 21 at the BC1(J3 54-pin Natural connector). The trigger of the inertia switch causes the BC1 to unlock doors.

Fig 1: Identifying Central Lock Circuit Diagram

Courtesy of BMW OF NORTH AMERICA, INC.