Brake light actuation, function - GF82.10-P-3010FQ
MODEL 218
Function requirements, general
- No overvoltage or undervoltage (on-board electrical system voltage U ≥7 ≤17.5 V)
- Terminal 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 powered by the Electronic Stability Program control unit (N30/4) (without code (233) DISTRONIC PLUS and without engine 157) or the Premium Electronic Stability Program control unit (N30/7) (with code (233) DISTRONIC PLUS or with engine 157) with 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 then uses this to generate the "Brake lights On" request and sends this via the chassis CAN (CAN E) (up to 28.02.2013) or chassis CAN 1 (CAN E1), front SAM control unit, and interior CAN to the rear SAM control unit with fuse and relay module (N10/2), and on vehicles with code (550) Trailer hitch, also to the trailer recognition control unit (N28/1).
In addition, each Electronic Stability Program control unit actuates the rear SAM control unit over a direct line (circuit 54) in order to counteract any delay in forwarding the request over the two data buses.
The rear SAM control unit routes this signal over a direct line to the trailer recognition control unit.
The rear SAM control unit actuates the following components:
- Left rear lamp unit (E3)
- Left brake light (E3e4) (as of 01.09.2014)
- Left brake light, taillight, and parking light (E3e9) (up to 31.08.2014)
- Right rear lamp unit (E4)
- Right brake light (E4e4) (as of 01.09.2014)
- Right brake light, taillight, and parking light (E4e9) (up to 31.08.2014)
- Center brake lamp (E21)
In vehicles with code (550) Trailer hitch, 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 respective Electronic Stability Program control unit sends the "Emergency braking" signal via the chassis CAN (up to 28.02.2013) or chassis CAN 1, front SAM control unit, and interior CAN to the rear SAM control unit and on vehicles 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 trailer recognition control unit then actuates the brake lights on the trailer via the trailer socket.
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-2057-97XAA |
| Overview of exterior lights system components | GF82.10-P-9998FQ |