Brake Light Actuation, Function - GF82.10-S-3010TRF
Model 447
with code XM0 (Facelift)
except code XM7 (MOPF II)
Function requirements, general
- No overvoltage or undervoltage
- "Circuit 15 ON"
The circuit status of circuit 15 is sent by the electronic ignition lock control unit (EZS) (N73) via the interior CAN (CAN B) to the signal acquisition and actuation module (SAM) control unit (N10/1).
Brake light actuation, general
The brake light actuation design can be adapted. In the event of emergency braking, the brake lights on the vehicle are actuated to flash on and off.
Brake light actuation function sequence
When the service brake is operated, the status of the brake lights switch (S9/3) is read in directly by the Electronic Stability Program (ESP) control unit (N30/4).
If the brake lights switch is defective, braking is detected by the Electronic Stability Program (ESP) control unit through the brake pressure.
The Electronic Stability Program (ESP) control unit sends a brake light request via the chassis CAN (CAN E), electronic ignition lock control unit (EZS), and interior CAN to the signal acquisition and actuation module (SAM) control unit.
On vehicles without code LG4 (LED tail lights, brake lights, and turn signal lights):
The signal acquisition and actuation module (SAM) control unit sends the brake lights actuation directly to the:
- The left rear lamp unit (E3), which then actuates the left taillight and left brake light (E3e4) directly.
- The right rear lamp unit (E4), which then actuates the right taillight and right brake light (E4e4) directly.
On vehicles with code LG4 (LED tail lights, brake lights, and turn signal lights):
The signal acquisition and actuation module (SAM) control unit sends the brake light actuation directly to the:
- Left brake light (E3/1e4)
- Right brake light (E4/1e4)
Brake light actuation for additional brake lamp:
The signal acquisition and actuation module (SAM) control unit sends the brake lights actuation directly to the:
- Additional brake lamp on tailgate (E21/2) (with code W65 (tailgate))
- Additional brake lamp on rear-end door (E21/1) (model 447.6/7 with code W50 (two-wing rear-end door, 180 degrees without window) or code W54 (two-wing rear-end door, 270 degrees))
- Additional brake lamp on separately opening rear window (E21/3) (model 447.8 with code W64 (Separately opening rear window))
If the parking brake and thus the parking brake indicator switch (S12) (model 447.6/7) or the electric parking brake indicator switch (S12/1) (model 447.8) is actuated while driving, all brake lights are actuated from a certain delay on.
The Electronic Stability Program (ESP) control unit reads in the status of the parking brake indicator switch or the electric parking brake indicator switch directly. It sends this status via the chassis CAN, electronic ignition lock control unit (EZS), and interior CAN to the signal acquisition and actuation module (SAM) control unit.
On vehicles with code Q22 (trailer coupling with non-removable ball head) or with code Q50 (trailer coupling with removable ball head):
The signal acquisition and actuation module (SAM) control unit forwards the brake light request on to the trailer recognition control unit (AAG) (N28/1). This actuates the trailer brake lights via the 13-pin trailer socket (X58).
Function sequence for emergency braking
On model 447 without code ET4 (Active Distance Assist DISTRONIC):
If, at a vehicle speed of > 50 km/h, maximum full-stop braking (vehicle deceleration > 7.5 m/s2 ) is initiated, all brake lights are actuated to flash on and off.
The Electronic Stability Program (ESP) control unit sends the "Emergency braking" signal via the chassis CAN, electronic ignition lock (EZS) control unit, and interior CAN to the signal acquisition and actuation module (SAM) control unit. The signal acquisition and actuation module (SAM) control unit actuates the brake lights with a clock frequency of 3 or 5 Hz.
The following clock frequencies are output, depending on the light sources used:
- For bulbs 3 Hz
- For LEDs 5 Hz
On model 447.8 with code ET4 (Active Distance Assist DISTRONIC):
If, at a vehicle speed of > 50 km/h, maximum full-stop braking (DISTRONIC active) is initiated, all brake lights are actuated to flash on and off.
On vehicles with code Q22 (trailer coupling with non-removable ball head) or with code Q50 (trailer coupling with removable ball head):
The signal acquisition and actuation module (SAM) control unit sends a signal via the interior CAN to the trailer recognition control unit (AAG). This actuates the trailer brake lights via the 13-pin trailer socket.
The following clock frequencies are output, depending on the light sources used on the trailer:
- For bulbs 3 Hz
- For LEDs 5 Hz
If the vehicle comes to a standstill from a speed of > 70 km/h after maximum full-stop braking, the hazard warning light function is automatically activated.
The emergency braking signal is reset if one of the following preconditions is met:
- Vehicle speed 0 km/h
- Vehicle deceleration < 6.5 m/s2
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