Brake Light Actuation, Function - GF82.10-P-3010LF

Model 217, 222 

Function requirements, general 

• No overvoltage or undervoltage
• Circuit 15 ON or "Standstill" signal not set

The electronic ignition lock control unit (N73) sends the status of terminal 15 to the rear SAM control unit (N10/8) via the interior CAN (CAN B).

The front SAM control unit (N10/6) also actuates the rear SAM control unit via a direct line (circuit 15) in order to counteract any delayed forwarding of the request via the CAN buses.

The Electronic Stability Program control unit (N30/4) transmits the "Standstill" signal to the rear SAM control unit via the suspension FlexRay (Flex E), electronic ignition lock control unit and interior CAN.

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 222.004/057/104/157/163/173) or the pedal angle sensor (B37/1) (model 222.004/057/104/157/163/173) is actuated. The Electronic Stability Program control unit directly reads in the status of the brake light switch or the signal of the pedal angle sensor and transmits the status of the service brake to the rear SAM control unit and also to the trailer recognition control unit (N28/1) in vehicles with code 550 (Trailer hitch) via the suspension FlexRay, electronic ignition lock control unit and interior CAN.

The Electronic Stability Program control unit also actuates the rear SAM control unit via a direct line (circuit 54) in order to counteract any delayed forwarding of the request via the CAN buses. The rear SAM control unit routes this signal via 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) (model 217 except CODE 460 (Canada version) and except CODE 494 (USA version), model 222)
  • Left taillight and brake light (E3e17) (model 222)
  • Left tail light (E3e18) (model 217 up to 30.11.2017, with code 460 (Canada version) or code 494 (USA version))
  • Left brake light and turn signal light (E3e21) (model 217 with CODE 460 (Canada version) or CODE 494 (USA version))
• Inner rear left lamp unit (E3/1) (model 217 up to 30.11.2017)
  • Inner left brake light (E3/1e9) (except CODE 460 (Canada version) and except CODE 494 (USA version))
• Right rear lamp unit (E4):
  • Right brake light (E4e4) (model 217 except CODE 460 (Canada version) and except CODE 494 (USA version), model 222)
  • Right taillight and brake light (E4e17) (model 222)
  • Right tail light (E4e18) (model 217 up to 30.11.2017, with code 460 (Canada version) or code 494 (USA version))
  • Right brake light and turn signal light (E4e21) (model 217 with CODE 460 (Canada version) or CODE 494 (USA version))

• Inner rear right lamp unit (E4/1) (model 217 up to 30.11.2017)
  • Inner right brake light (E4/1e9) (except CODE 460 (Canada version) and except CODE 494 (USA version))
• Center brake lamp (E21)

In vehicles with code (550) Trailer hitch, the trailer recognition control unit receives the incoming information and actuates the brake lights of the trailer via the trailer socket (X58).

Model 217 as of model year 2018 except code 460 (Canada version) except code 494 (US version)

If the low beam is deactivated (during the day) and the rear fog light is deactivated, the left tail light and inner left tail light (E3/1e2) as well as the right tail light and inner right tail light (E4/1e2) are also actuated. These are completely and immediately switched on. When switching off, however, a lighting event occurs in the tail lights mentioned above: The entire surface of both lights on each side is switched off from top to bottom at staggered intervals. The duration of the lighting event lasts approx. t = 3 s. In the event of failure of individual system components for the vehicle's rear lights, no staging will take place.

Model 217 up to model year 2018 except code 460 (Canada version) except code 494 (US version)

The inner left or inner right brake light is switched off with active rear fog light actuation.

If, during a journey, the electric parking brake switch (S76/15) is operated, the brake lights and the center brake lamp are actuated as from a certain deceleration.

For model 222 as of 01.06.2017 and model 217 as of 01.12.2017, the following applies: The Electronic Stability Program control unit directly reads in the status of the electric parking brake switch and transmits the "Brake light ON" request to the rear SAM control unit and also to the trailer recognition control unit in vehicles with code 550 (Trailer hitch) via the suspension FlexRay, electronic ignition lock control unit and interior CAN.

For model 222 up to 31.05.2017 and model 217 up to 30.11.2017, the following applies: The electric parking brake control unit (N128) directly reads in the status of the electric parking brake switch and transmits the "Brake light ON" request to the rear SAM control unit and also to the trailer recognition control unit in vehicles with code 550 (Trailer hitch) via the peripherals CAN (CAN PER), electronic ignition lock control unit and interior CAN.

If emergency braking (BAS active or vehicle deceleration a > 7.5 m/S2) is initiated at a vehicle speed of v > 25 km/h, for vehicles except code 460 (Canada version) and except code 494 (USA version), the brake lights and the center brake lamp are actuated (flashing).

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 over the chassis FlexRay, electronic ignition lock control unit, and interior CAN to the rear SAM control unit and in vehicles with CODE 550 (Trailer hitch), also 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 or 5 Hz and on vehicles with CODE 550 (Trailer hitch) it sends a signal that defines the duration of the dark phase 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 following 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 < 10 km/h
• Vehicle deceleration a < 6.5 m/s5

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