2005 AUDI A6 light

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Function of the light sensor
In order to detect certain ambient conditions, such
as tree-lined avenues or routes through tunnels, the
light sensor registers the light intensity in two
areas.
The global field describes the direct brightness on
the vehicle, while the fore-field describes the
lighting conditions in the section of road lying
ahead of the vehicle. This is activated using the
"Auto" setting on the rotary light switch.
Tasks of the rain sensor
The following functions are implemented,
depending on the amount of water on the
windscreen:
– Switch the wiper on and off automatically at
seven different speeds
– Activate the driving light when it is raining
Activation
The rain sensor is activated by positioning the wiper
stalk to the "Intermittent" setting. The driver can
then set four sensitivity ranges using the regulator
for windscreen wiper intermittent operation.
A reference wiper function (wiper action when the
rain/light sensor is activated) is no longer necessary
with this system. This means that the wiper stalk
can always remain at the "Intermittent" setting.
For safety reasons, however, the rain sensor
operation is only activated in this case when a
driving speed of more than 16 km/h is reached, or
when the sensitivity on the regulator for windscreen
wiper intermittent operation is changed.
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326_091
Global field
Fore-field
Note
Manually switched wiper intervals have
priority
Light sensor
Rain sensor
photodiode is
also used

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Function of the rain sensor
The rain sensor uses the physical light refraction
principle to register the amount of moisture on the
windscreen. The circular LEDs integrated in the
sensor emit infrared light through the windscreen
from within the interior of the vehicle.
If the windscreen is dry, the infrared light is
reflected on the surface of the glass.
The photodiode integrated in the centre of the
sensor thus records a high light intensity.
If the windscreen is covered with moisture, the
optical properties on the surface of the glass
change. Light now emerges from the windscreen
surface through the light refraction caused by water
drops. As a result, less light is reflected back and the
photodiode records a lower light intensity (light
dispersion principle).
Diagnosis
The control unit for on-board power supply J519 is
used for diagnostic procedures on the sensor for
rain and light detection.
Convenience electrics
326_091 LEDs
Photodiode
326_093Windscreen surface
LED
Photodiode
LED 326_080

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The control unit for wiper motor J400 was
redesigned for use in the new Audi A6 ’05. As is
already the case in the Audi A8 ‘03 and Audi A3 ’04,
the control unit and wiper motor are integrated into
one housing.
It is linked to the control unit for on-board power
supply J519 as a LIN-slave control unit.
Functions
– Intermittent
– Intermittent stages (four)
–One-touch wiping
– Wiper function stage 1
– Wiper function stage 2
– Wipe over again 5 seconds after the last
wash-and-wipe action
(at vehicle speed > 5 km/h only)
– Rain sensor function (see Sensor for rain and
light detection G397)
– Service setting
– Alternating parking position (can be coded)
Function diagram
G397 Sensor for rain and light detection
J400 Control unit for wiper motor
J519 Control unit for on-board power supply
Reference
For further information on the control unit
for wiper motor J400, please refer to the
SSP 287, Audi A8 ‘03 – Electrical
Components.
Note
The control unit for on-board power
supply J519 now activates the windscreen
washer pump V5.
326_081
Control unit for wiper motor J400
326_104

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The central control unit for the convenience
system J393, with which you may be familiar from
the Audi A8 '03, is used in the Audi A6 ’05. The tasks
and functions have been adapted according to
requirements.
The control unit is a participant on the
CAN Convenience data bus.
Master functions
The master functions of the central control unit for
the convenience system are as follows:
– Direction indicator master
– Central locking master
– Interior lighting master
– LIN master for alarm horn H12 and sensor for
passenger compartment monitoring G273
Other functionalities
In addition to the master functions, other functions
are also available in the central control unit for the
convenience system. The power outputs integrated
in the control unit activate the following loads:
– Back lights
–Rear sun blind
– Rear window heating
– Rear footwell lights
–Boot light
– Tailgate/boot lid release
Ve rs i on s
Two versions of the central control unit for the
convenience system are available:
–Basic
– High-Line (with rear sun blind/anti-theft warning
system/light package for ambient lighting/area
lighting)
Central control unit for convenience system J393
326_113

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326_121
Installation position
The central control unit for the convenience system
is installed above the battery in the rear right of the
boot.
System overview
Convenience electrics
– Tailgate/boot lid "softtouch"
– Tailgate/boot lid locking cylinder closed
– Brake light switch
– B rake li ght signal from control u ni t fo r ABS with
EDL J104
– Garage door opener (adaptation flashing)– Crash input
– Tailgate/boot lid contact
–Tank plug lock detection (USA)
– Alarm horn H12 (via LIN bus)
– Sensor for passenger compartment
monitoring G273 (via LIN bus)
– Rear footwell lights, left and right
– Boot light
– Motor for rear sun blind V91
– Motor for tank cap locking V155
– Motor for tailgate/boot lid central locking V53
– Interior lighting roof module
– Passenger compartment light
– Alarm horn H12 (via LIN bus)– High-level brake light (LED)
– Tail light, left and right
–Brake light, left and right
– Reversing light, right
–Rear fog light, left
– Number plate light
– Heated rear window Z1
– Rear direction indicator light, left and right
– Level control unit J197
(doors open/closed) The central control unit for the convenience system J393 receives the following input signals:
The central control unit for the convenience system J393 activates the following loads:
326_114

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Interior lighting control
Standard equipment function
The standard function includes activating the inside
light in the roof lining, the front footwell lights, the
glove compartment light and the boot light.
The central control unit for the convenience
system J393 activates the inside light in the roof
lining, the boot light and the glove compartment
light directly via its own outputs and inputs. The
control unit for on-board power supply J519
activates the front footwell lights via CAN messages
from the central control unit for the convenience
system J393.
Additional equipment function (light package)
The light package additional equipment also
includes a door contour light in every door as well
as footwell lights (front and rear), which are based
on LED technology. The door contour lighting is
activated by the door control unit, which receives
the CAN messages for this from the central control
unit for the convenience system J393.

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Function diagram
Convenience electrics
C18 Interference filter for windscreen antenna
E26 Switch for glove compartment light
F124 Contact switch for lock cylinder for
tailgate/boot lid, anti-theft warning system,
central locking
F147 Contact switch for make-up mirror
driver’s side
F148 Contact switch for make-up mirror
passenger’s side
F218 Switch for tailgate/boot lid central locking
F248 Button for tailgate/boot lid lock cylinder
release
G273 Sensor for passenger compartment
monitoring
H12 Alarm hornJ9 Relay for rear window heater
J393 Central control unit for convenience system
L46 Lamp for rear fog light, left
M2 Lamp for tail light, right
M4 Lamp for tail light, left
M6 Lamp for direction indicator light, rear left
M8 Lamp for direction indicator light, rear right
M9 Lamp for left brake light
M10 Lamp for right brake light
M17 Lamp for reversing light, right
M25 Lamp for high-level brake light
M49 Lamp for tail light 2, left
M50 Lamp for tail light 2, right
M54 Lamp for tail light 3, left
M55 Lamp for tail light 3, right

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326_120
V53 Motor for tailgate/boot lid central locking
V91 Motor for rear sun blind
V155 Motor for tank cap locking
W6 Glove compartment light
W14 Illuminated make-up mirror, passenger’s side
W18 Boot light, left
W20 Illuminated make-up mirror, driver’s side
W35 Boot light, right
W45 Footwell light, rear left
W46 Footwell light, rear right
X Number plate light
Z1 Heated rear window Additional signals
1CAN Convenience High
2CAN Convenience Low
3 Brake light switch F
4 ESP brake signal from control unit for ABS
with EDL J104
5 Crash signal from airbag control unit J234
6 "Doors OPEN" signal to level control unit J197
7 "Adaptation flashing" signal from control unit
for garage door opening J530
8 "Release" signal to motor for sliding roof V1
9 + 10 "Interior light" activation signal
to roof module W1