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

MODEL 207.3/4 as of model year 2014 

Function requirements, general 

• No overvoltage or undervoltage (operating voltage range U ≥ 7 ≤ 17.5 V)
• Circuit 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 lights switch (S9/1) is powered by the Electronic Stability Program control unit (N30/4) over 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 records the status of the service brake and sends this over chassis CAN 1 (CAN E1), the front SAM control unit and the 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, the Electronic Stability Program control unit actuates the rear SAM control unit via a direct line (circuit 54) in order to counteract any delay in the forwarding of 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 receives the request 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 request 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/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 Electronic Stability Program control unit sends the "emergency braking" signal over chassis CAN 1, the front SAM control unit and the interior CAN to the rear SAM control unit and for 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 Electronic Stability Program control unit resets the emergency braking signal if one of the following requirements 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-2057-97EAB
	Overview of exterior lights system components		GF82.10-P-9998CAM