Function requirements, general
No overvoltage or undervoltage
"Ambient illumination" function activated in "Settings", "Light" menu in instrument cluster (A1)
Rain/light sensor (B38/2) signals "Darkness detected"
Exterior lights switch (S1) in position "AUTO"
Headlamp switch-off delay (SWA), general
The SWA function is used for leaving and finding the vehicle safely in darkness by switching on the ambient illumination.
A differentiation is made between the following versions of the left front lamp unit (E1) and the right front lamp unit (E2) in accordance with the vehicle equipment:
Halogen version lamp units (except CODE 615 (Bi-xenon headlamp unit with integrated curve illumination) and except CODE 621 (Intelligent Light System (left-hand traffic)) and except CODE 622 (Intelligent Light System (right-hand traffic)))
Xenon version lamp units (with CODE 615 (Bi-xenon headlamp unit with integrated curve illumination) or CODE 621 (Intelligent Light System (left-hand traffic)) or CODE 622 (Intelligent Light System (right-hand traffic)))
Halogen version lamp units:
The parking and standing light functions are output using conventional light sources (bulbs).
The SAM control unit (N10) actuates the following components in the front lamp units for this:
Left front lamp unit:
Left front standing light and parking light (E1e3)
Left front side marker light (E1e6)
Right front lamp unit
Right front standing light and parking light (E2e3)
Right front side marker lamp (E2e6)
Lamp units in xenon design:
Instead of conventional bulbs, light emitting diodes (LED) are used to output the parking and standing light functions. To this end, the left front actuation module, LED exterior lighting (E1n7) is located on the side of the left front lamp unit and the right front actuation module, LED exterior lighting (E2n7) is located on the side of the right front lamp unit.
To output the parking and standing light functions, the SAM control unit switches a signal voltage (circuit 57) through to the front actuation modules, LED exterior lighting.
The left front actuation module, LED exterior lighting actuates the following components in the left front lamp unit:
Left front standing and parking lamp
Left front side-marker lamp
The right front actuation module, LED exterior lighting actuates the following components in the right front lamp unit:
Right front standing and parking lamp
Right front side-marker lamp
The front actuation modules, LED exterior lighting are diagnosed via the headlamp control unit (N71/1).
The SWA function is comprised of the following subfunctions:
Function sequence for outer OFF delay function
Function sequence for locator lighting (AFB)
Function sequence for outer OFF delay function
After the driver switches off the engine (change in status of circuit 15 ON to circuit 15R ON) the SWA function is then requested.
The following information is evaluated by the SAM control unit for output of the SWA function:
Activated SWA function, sent by the instrument cluster via interior CAN (CAN B)
Status of circuit 15, sent by the electronic ignition lock control unit (N73) over interior CAN
Rain/light sensor status, read in via roof LIN (LIN B13)
Status of exterior lights switch, read in directly
After switching off the engine, the ambient illumination is switched on for a fixed time interval of t = 60 s. The time interval starts again by opening a vehicle door. The liftgate is assessed as a vehicle door.
If all vehicle doors are closed again, the function is restarted.
MODEL 166
up to model year 2016
with CODE 501 (360 degree camera)
To be able to ensure the 360° camera function even in darkness, the ambient illumination in the respective outside mirror housings is activated depending on the ambient brightness. For this, the 360° camera control unit (N148) sends the request "Outside mirror ambient illumination ON" via chassis CAN 2 (CAN E2), electronic ignition lock control unit and interior CAN to the SAM control unit. The SAM control unit then decides, depending on the ambient brightness, whether the left outside mirror ambient lamp (M21/1e1) in the left outside mirror (M21/1) and the right outside mirror ambient lamp (M21/2e1) in the right outside mirror (M21/2) are switched on.
The status of the front doors is sent by the left front door control unit (N69/1) and the right front door control unit (N69/2), the status of the rear doors by the left rear door control unit (N69/3) and the right rear door control unit (N69/4) and the status of the liftgate by the rear SAM control unit (N10/8) via interior CAN to the SAM control unit.
The SAM control unit evaluates all of the relevant information and transmits the request to switch on the ambient illumination via interior CAN to the following control units:
Left front door control unit
Right front door control unit
Trailer recognition control unit (N28/1) (with CODE 550 (Trailer hitch))
Halogen version lamp units:
The SAM control unit actuates the following exterior lights components:
Vehicle front:
Left front standing and parking lamp
Right front standing and parking lamp
Rear area:
Outer left taillight (E3e16) in left rear lamp unit (E3)
Inner left taillight (E3/1e2) in inner left rear lamp unit (E3/1)
Outer right taillight (E4e16) in right rear lamp unit (E4)
Inner right taillight (E4/1e2) in inner right rear lamp unit (E4/1)
Left liftgate license plate lamp (E19/3)
Right liftgate license plate lamp (E19/4)
Lamp units in xenon design:
The SAM control unit actuates the following exterior lights components:
Vehicle front:
Left daytime running lights headlamp (E1/3)
Right daytime running lights headlamp (E2/3)
Left front standing light and parking light via the left front actuation module, LED exterior lighting
Right front standing light and parking light via the right front actuation module, LED exterior lighting
Actuation of the exterior lights components in the rear area is identical in both versions.
The left front door control unit actuates the left outside mirror ambient lamp.
The right front door control unit actuates the right outside mirror ambient lamp.
The trailer recognition control unit actuates the following components for the exterior lights on the trailer via the trailer socket (X58) (except CODE 460 (Canada version) and except CODE 494 (USA version)) or via the 7-pin trailer socket (X58/11) (with CODE 460 (Canada version) or CODE 494 (USA version)):
Taillamps and parking lamps
License plate lights
The active SWA is terminated by switching on circuit 15 or by triggering an anti-theft alarm system (ATA [EDW]) alarm (with CODE 551 (Anti-theft alarm system (ATA [EDW]))).
Function sequence for AFB
When the vehicle is unlocked using a radio frequency or infrared, the ambient illumination is switched on for a period of t = 40 s (time required for automatic relocking).
The electronic ignition lock control unit sends the status of the central locking via interior CAN to the SAM control unit. The SAM control unit evaluates this, actuates all components of the ambient illumination and sends the request to switch on the ambient illumination via interior CAN to the front door control units and the trailer recognition control unit.
The components of the ambient illumination are actuated as described for the SWA function.
The locator lighting function is terminated when a door is opened, when circuit 15C is switched on or when an ATA [EDW] alarm is triggered.
The headlamp switch-off delay and locator lighting functions run in parallel if necessary. An active headlamp switch-off delay (SWA) function is not terminated by a requested AFB function and vice versa.
Referenced documents
- gf8210p9998gr Overview of exterior lights system components