Brake light/brake light test switch
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 |