Brake light/brake light test switch
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.
Two switches are fitted on the brake pedal which supply the following signals:
- S_BLS brake light switch
- S_BLTS Brake light test switch
The CAS/FEM control unit evaluates these signals for the purpose of registering brake operation. The CAS/FEM control unit transmits the signals via a CAN bus to the DME/DDE control unit.
The brake light switch connects to ground, the brake light test switch connects to positive. Both signals are checked for plausibility.
The following table shows how the signals behave:
| Brake light switch is | Brake light test switch is | |
|---|---|---|
| Brake pedal operated | open | closed |
| Brake pedal not operated | closed | open |