Setpoint value table of brake light switch: Notes
WARNING: This page does not describe the selected car, but rather 7 other vehicles, including the 2017 BMW X3, 2016 BMW X3, 2015 BMW X3, 2014 BMW X3, and 2013 BMW X3. However, it is still accessible from the selected car via links, so may be relevant.
There are two switches installed on the break pedal. The brake light switch and brake light test switch. Both signals most behave correctly in order for a operation of the brake to be detected.