Brake Lamp: Description and Operation

GF82.10-P-3010GM Stop Lamp Actuation, Function

Function requirements, brake light actuation, general
^ Circuit 15 On

The circuit status is made available on the interior CAN by the EIS [EZS] control unit (N73).

Brake light actuation, general
Corresponding to the request the brake light actuation realizes a static or flashing actuation of the brake lights on the vehicle.

Brake light actuation is comprised of the following subfunctions:
^ Function sequence, static brake lights
^ Function sequence, adaptive brake lights

Function sequence, static brake lights
Actuation of the service brake is detected by the BAS release switch (A7/7s1) in the BAS brake booster (A7/7).
The ESP control unit (N47-5) reads in the status of the BAS release switch directly and makes it available on the engine compartment CAN.
The central gateway control unit (N93) forwards this to the rear SAM control unit (N10/8) via the interior CAN.
At the same time the request "brake light On" (circuit 54) is forwarded from the ESP control unit directly to the rear SAM control unit to counteract any time delay in forwarding the request via the engine compartment CAN and the interior CAN.

The rear SAM control unit actuates the following components:
- Model 164.1 without code (849) Spare tire holder/spare tire
- Left brake light (E3e4)
- Right brake light (E4e4)
- Center high-mounted brake lamp (E21)

- Model 164.8 without code (849) Spare tire holder/spare tire
- Left brake light
- Right brake light
- Center high-mounted brake lamp
- Left taillight, side marker lamp, parking light (E3e8)
- Right taillight, side marker lamp, parking light (E4e8)

- Model 164.1/8 with code (849) Spare tire holder/spare tire
- Left brake light and taillight (E3/5e4)
- Right brake light and taillight (E4/5e4)
- Center high-mounted brake lamp

- Model 251.0/1
- Left brake light, taillight, parking light and side-marker lamp (E3e9)
- Right brake light, taillight, parking light and side-marker lamp (E4e9)
- Center high-mounted brake lamp

- Brake lights of trailer via the
- Trailer hitch socket, 13-pin (X58)
(with code (550) Trailer hitch, without code (460) Canada version or without code (494) USA version
- Trailer hitch socket, 7-pin (X58/11)
(with code (550) Trailer hitch and code (460) Canada version or code (494) USA version

Additional function requirements, adaptive brake lights
^ Brake operated
^ Vehicle speed v > 50 km/h
^ Brake Assist system active or vehicle deceleration a > 7.5 m/s2
^ Manual hazard warning flashing inactive

Function sequence, adaptive brake lights
The vehicle speed and deceleration are determined by the ESP control unit. In the event of danger braking the ESP control unit places a corresponding signal on the engine compartment CAN. The central gateway control unit forwards this signal to the rear SAM control unit via the interior CAN.

The rear SAM control unit actuates the brake lights, the center high-mounted brake lamp and if applicable the brake lights on the trailer with a frequency of f = 5 Hz for the duration of the signal (at least t = 1 s).

If the vehicle comes to a standstill after danger braking, the hazard warning flasher function is activated automatically.

The danger braking signal is reset if one of the following preconditions is met:
- Vehicle speed v < 5 km/h
- Vehicle deceleration a < 6.5 m/s 2 for t = 150 ms