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

MODEL 212 as of model year 2014 

Function requirements, general

• No overvoltage or undervoltage (operating voltage range U ≥ 7 ≤ 17.5 V)
• Terminal 15 ON

The electronic ignition switch control unit (N73) sends the status of circuit 15 to the front SAM control unit with fuse and relay module (N10/1) via 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 lights switch (S9/1) is supplied with power from circuit 15 by the Electronic Stability Program control unit (N30/4) (model 212 (except 212.074/092/095/098/274/292/298) without code (233) DISTRONIC PLUS), by the regenerative braking system control unit (N30/6) (model 212.095/098/298) or by the Premium Electronic Stability Program control unit (N30/7) (model 212 (except 212.095/098/298) with code (233) DISTRONIC PLUS, model 212.074/092/274/292).

When the service brake is operated, the brake lights switch switches the applied voltage through to the Electronic Stability Program control unit or to the regenerative braking system control unit. The Electronic Stability Program control unit or the regenerative braking system control unit uses this to generate the request for braking, implements this and sends the status of the service brake via 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 is with code (550) Trailer hitch, also to the trailer recognition control unit (N28/1).

The Electronic Stability Program control unit or the regenerative braking system control unit also actuates the rear SAM control unit via a direct line (circuit 54) in order to counteract any delay in the forwarding of the request via 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 receives the status of the service brake and the circuit 54 signal and actuates the following components:

• Left rear lamp unit (E3):
  • Left brake light (E3e4)
  • Left taillight and brake light (E3e17)
• Right rear lamp unit (E4):
  • Right brake light (E4e4)
  • Right taillight and brake light (E4e17)
• Center brake lamp (E21)

The trailer recognition control unit receives the signals and actuates the brake lights of the trailer via 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/s) 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 to the front SAM control unit over the interior CAN. The Electronic Stability Program control unit or the regenerative braking system control unit sends the "emergency braking" signal via 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 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-2057-97DAB
	Overview of exterior lights system components		GF82.10-P-9998FLM