Two switches are fitted on the brake pedal which supply the following signals:
The DDE control unit evaluates the signals for the purpose of registering brake operation.
The brake light switch connects to earth, the brake light test switch connects to B+. 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 |
Fault code ”Brake light/brake light test switch” is stored if the signals are not plausible. Cruise control is deactivated as a result.