Double Lock/Unlock Function

Also known as central arrest, this motor is activated only when the vehicle is locked from the exterior at the driver's door lock with a key or when the GM receives a lock request from the Key-less entry system. In this case the double lock motor is activated simultaneously with the single lock motor.

The function of the double lock motor is to mechanically offset an internal rod disabling it from unlocking the vehicle from the interior.

This prevents the doors from being unlocked by any means except from an unlock request at the driver's door or via the Key-less entry.

Fig 1: Identifying Double Lock/Unlock Function

Courtesy of BMW OF NORTH AMERICA, INC.