Brake light actuation, function - GF82.10-P-3010RF

MODEL 205, 253 

Function requirements, general 

• No overvoltage or undervoltage
• Terminal 15 ON

The electronic ignition lock control unit (N73) sends the status of circuit 15 to the rear SAM control unit (N10/8) 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 

When the service brake is operated, the brake light switch (S9/1) (except model 205.012/047/147/212/247) or the pedal angle sensor (B37/1) (model 205.012/047/147/212/247) is actuated. The Electronic Stability Program control unit (N30/4) reads in the status of the brake light switch or the signal of the pedal angle sensor directly and sends the status of the service brake via chassis FlexRay (Flex E), electronic ignition lock control unit and interior CAN to the rear SAM control unit and, on vehicles with code 550 (Trailer hitch), also to the trailer recognition control unit (N28/1).

The Electronic Stability Program control unit also actuates the rear SAM control unit over a direct line (circuit 54). The rear SAM control unit routes this signal over a direct line to the trailer recognition control unit.

In the event of a defective brake light switch or a defective pedal angle sensor, any braking is registered by the Electronic Stability Program control unit by way of the brake pressure.

The rear SAM control unit receives the status of the service brake and actuates the following components:

• Left rear lamp unit (E3):
  • Left brake light (E3e4)
  • Left taillight (E3e18) (model 205.0/1 with CODE 631 (Static left-hand traffic LED headlamp) or CODE 632 (Static right-hand traffic LED headlamp) or CODE 640 (High Performance LED) or CODE 641 (DYNAMIC LEFT-HAND TRAFFIC LED HEADLAMP) or CODE 642 (DYNAMIC RIGHT-HAND TRAFFIC LED HEADLAMP), model 205.2/3/4)
• Right rear lamp unit (E4):
  • Right brake light (E4e4)
  • Right taillight (E4e18) (model 205.0/1 with CODE 631 (Static left-hand traffic LED headlamp) or CODE 632 (Static right-hand traffic LED headlamp) or CODE 640 (High Performance LED) or CODE 641 (DYNAMIC LEFT-HAND TRAFFIC LED HEADLAMP) or CODE 642 (DYNAMIC RIGHT-HAND TRAFFIC LED HEADLAMP), model 205.2/3/4)
• Center brake lamp (E21)

The trailer recognition control unit receives the status of the service brake and actuates the trailer brake lights over the trailer socket (X58).

The brake lights and center brake lamp are actuated if the electric parking brake switch (S76/15) is pressed while driving.

Vehicles without engine 177 

The Electronic Stability Program control unit reads in the status of the electric parking brake switch directly and sends the "Brake lights ON" request over the chassis FlexRay, electronic ignition lock control unit and interior CAN to the rear SAM control unit and on vehicles with CODE (550 (Trailer hitch), also to the trailer recognition control unit.

Vehicles with engine 177 

The electric parking brake control unit (N128) reads in the status of the electric parking brake switch directly, and sends the "Brake light ON" request over the periphery CAN (CAN PER), electronic ignition lock control unit and the interior CAN to the rear SAM control unit, and on vehicles with CODE 550 (Trailer hitch), also to the trailer recognition control unit.

If, at a vehicle speed of v > 50 km/h, emergency braking (BAS active or vehicle deceleration a > 7.5 m/s² ) is initiated, then the brake lights and the center brake lamp are actuated to flash on and off.

The instrument cluster (A1) sends the vehicle speed over the user interface CAN (CAN HMI), electronic ignition lock control unit and the interior CAN to the rear SAM control unit.

The Electronic Stability Program control unit sends the "Emergency braking" signal via the chassis FlexRay, electronic ignition lock control unit, and interior CAN to the rear SAM control unit and additionally in 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 at a frequency of f = 3 or 5 Hz for the duration of the signal. In vehicles with code (550) Trailer hitch, the rear SAM control unit sends a corresponding signal that defines the period for which the dark phase is set, over the interior CAN to the trailer recognition control unit. The trailer recognition control unit then actuates the trailer brake lights through the trailer socket.

The following frequencies are output, depending on the light sources used on the trailer:

• For bulbs, f = 3 Hz
• For LEDs f = 5 Hz

If the vehicle comes to a standstill from a speed of v > 70 km/h after emergency braking, the hazard warning flasher function is automatically activated.

The danger braking signal is reset if one of the following preconditions is met:

• Vehicle speed v = 0 km/h
• Vehicle deceleration a < 6.5 m/s²

Electrical function schematic for brake light actuation	PE82.10-P-2057-97FBA
Overview of exterior lights system components	GF82.10-P-9998RF