Brake light actuation, function - GF82.10-P-3010CE
MODEL 204.0 /2 as of model year 2009 /YoM 08
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 switch control unit (N73) transmits circuit 15 status to the front SAM control unit with fuse and relay module (N10/1) via the interior CAN (CAN B).
Brake light actuation, general
Corresponding to the request the brake light actuation realizes a static or flashing actuation of the brake lights on the vehicle.
The brake light actuation is comprised of the following subfunctions:
- Function sequence, static brake lights
- Function sequence, adaptive brake lights
Function sequence, static brake lights
The brake light switch (S9/1) is supplied using circuit 15 by the front SAM control unit. When the service brake is being operated, the voltage that is present is switched through to the Electronic Stability Program control unit (N30/4). The Electronic Stability Program control unit uses this to generate the "brake lights ON" signal and sends this over the chassis CAN (CAN E), front SAM control unit and interior CAN to the rear SAM control unit with fuse and relay module (N10/2) as well as for vehicles with code (550) Trailer hitch 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 brake light, taillight and parking light (E3e9)
- Inner left brake light and taillight (E3e10) (with model 204.0/2/3)
- Right brake light, taillight and parking light (E4e9)
- Inner right brake light and taillight (E4e10) (with 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).
Additional function requirements, adaptive brake lights
- Vehicle speed v > 25 km/h
- Brake Assist system active or vehicle deceleration a > 7.5 m/s2
Function sequence, adaptive brake lights
In the event of any emergency braking the brake lights and the center brake lamp are actuated and they flash on and off.
The instrument cluster (A1) sends the vehicle speed to the front SAM control unit via interior CAN.
The Electronic Stability Program control unit sends the "emergency braking" signal over the chassis CAN, front SAM control unit and the interior CAN to the rear SAM control unit and for 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 center brake light for the duration of the signal at a frequency of f = 3 to 5 Hz and also sends a corresponding signal over the interior CAN to the trailer recognition control unit, which defines the time duration for the dark phase set.
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 always automatically activated if braking occurred from a speed of v > 70 km/h.
The danger braking signal is reset if one of the following preconditions is met:
- Vehicle speed v < 10 km/h
- Vehicle deceleration a < 6.5 m/s2
| Electrical function schematic for brake light actuation | PE82.10-P-2057-97FAB | ||
| Overview of exterior lights system components | GF82.10-P-9998CE |