Brake light actuation, function - GF82.10-P-3010CE
MODEL 204.0/2 as of model year 2009
MODEL 204.3
MODEL 204.9
Function requirements, general
- No overvoltage or undervoltage (operating voltage range U ≥ 7 ≤ 17.5 V)
- Circuit 15 ON
The electronic ignition lock control unit (N73) transmits the circuit 15 status to the front SAM control unit with fuse and relay module (N10/1) over the interior CAN (CAN B).
Brake light actuation, general
The brake light actuation design can be adapted. In the event of emergency braking the brake lights on the vehicles are actuated to flash on and off.
Brake light actuation function sequence
The brake light switch (S9/1) is supplied with voltage by the front SAM control unit (model 204.0/2/3 up to 31.5.13, model 204.9) or by the Electronic Stability Program control unit (N30/4) (model 204.0/2/3 as of 1.6.13) via circuit 15. When the service brake is operated, the brake lights switch switches the applied voltage through to the Electronic Stability Program control unit. The Electronic Stability Program control unit generates the brake light actuation request from this, and makes it available on the chassis CAN (CAN E). The front SAM control unit receives the request and relays it via interior CAN to the rear SAM control unit with fuse and relay module (N10/2) and on vehicles with code (550) Trailer hitch additionally to the trailer recognition control unit (N28/1).
The Electronic Stability Program control unit also actuates the rear SAM control unit and the trailer recognition control unit via a direct line (circuit 54), to counteract any delay in the forwarding of the request via the two data buses.
The rear SAM control unit receives the request and actuates the following components:
- Left rear lamp unit (E3)
- Left brake light (E3e4) (on model 204.9 as of 1.6.12)
- Left brake light and taillight and parking light (E3e9) (except model 204.9 as of 1.6.12)
- Inner left brake light and taillight (E3e10) (on model 204.0/2/3)
- Right rear lamp unit (E4)
- Right brake light (E4e4) (on model 204.9 as of 1.6.12)
- Right brake light and taillight and parking light (E4e9) (except model 204.9 as of 1.6.12)
- Inner right brake light and taillight (E4e10) (on model 204.0/2/3)
- Center brake lamp (E21)
The trailer recognition control unit receives the request and actuates the brake lights on the trailer over the trailer socket (X58).
If, at a vehicle speed of v > 25 km/h, emergency braking (Brake Assist active or vehicle deceleration a > 7.5 m/s2 ) is initiated, then the brake lights and the center brake lamp are actuated to flash. The instrument cluster (A1) sends the vehicle speed to the front SAM control unit over the interior CAN. The Electronic Stability Program control unit sends the "Emergency braking" signal via chassis CAN, front SAM control unit and interior CAN to the rear SAM control unit and, on vehicles as of 1.6.09 with code (550) Trailer hitch, to the trailer recognition control unit. The rear SAM control unit actuates the brake lights and the center brake lamp for the duration of the signal at a frequency of f = 3 to 5 Hz and sends a signal that defines the period for the configured dark phase via interior CAN to the trailer recognition control unit.
The following frequencies are output, depending on the light sources used on the trailer:
- For bulbs, f = 3 Hz
- For light-emitting diodes, f = 5 Hz
If the vehicle comes to a standstill following emergency braking, the hazard warning flasher function is automatically activated if braking occurred from a speed of v > 70 km/h.
The emergency stop signal is reset if one of the following preconditions is fulfilled:
- Vehicle speed v < 10 km/h
- Vehicle deceleration a < 6.5 m/s 2
| Electrical function schematic for brake light actuation | MODEL 204.0/2 as of model year 2009MODEL 204.3MODEL 204.9 up to model year 2013 | PE82.10-P-2057-97FAB | |
| MODEL 204.9 as of model year 2013 | PE82.10-P-2057-97FAC | ||
| Overview of exterior lights system components | GF82.10-P-9998CE |