OK, installed the unit.
The most logical place to connect the unit is to get required wires from steering wheel harness. That involves removing cover under the steering wheel. There's plenty of space to attach the unit with double sided 3M VHB tape or to hide the unit under noise insulation.
Although unit will be connected to steering wheel harness I'll be physically installing the unit on passenger side of the car above the glove box since there are OEM relay slots there. Snaking wire to other side of the car is not covered in this writeup as I only wanted to document what we connect with what to make the unit functional in A8 D2, so this is 'reduced' writeup, skipping some obvious steps.
It has worked on my car (February 2002) and I can't guarantee it'll work on your car. Please check wiring diagrams.
The unit comes with 5 wires:
1. brown -- (15) ground
2. black/white -- (31) ignition controlled +12V
3. white/green -- (49a) blinker common
4. white - (49L) blinker left
5. green - (49R) blinker right
Ground and ignition are easy to find. This write up will concentrate on putting our hands on last 3 wires without having to disassemble steering column.
1. Remove cover under steering wheel:
2. Steering wheel harness is secured with U-shape metal bracket:
3. Remove bracket and remove adhesive fabric tape:
4. Put aside the 3 wires:
1. black/white/green - (49a) blinker common
2. black/white - (49L) blinker left
3. black/green - (49R) blinker right
Here they are:
Two things:
A). Make sure you choose 1 sq.mm wires. There are thinner wires of the same color combinations in the harness, 0.35 sq.mm -- we don't need those. They are too thin. B). Black/white means black color wire with white stripe. It doesn't mean white wire with black stripe -- be careful.
5. (49a) blinker common. Solder black/white/green wire from steering wheel harness with white/green wire of the unit:
6. (49L) blinker left. Solder black/white wire from steering wheel harness with white wire of the unit:
7. (49R) blinker right. Solder black/green wire from steering wheel harness with green wire of the unit:
8. (31) ignition controlled +12V. This obviously exist in steering wheel harness, but I took it from fuse box. It is rightmost 15A fuse in yellow bar. Behind the fuse you'll find thick black/blue wire. This is our ignition. Connect it with black/white wire of the unit. Make sure length of wire allows you to hide the unit where you want it to be. Extend wire if needed.
9. (15) ground. Interestingly, there is bunch of brown ground wires in steering wheel harness, but they are all too thin for us: 0.35 sq.mm. We need 1 sq.mm ground. So I organised my own ground by attaching to fuse box fox. That bolt is welded to chassis of the car. No picture.
10. Insulate and put everything back. I use 3M insulation tape and Certoplast fabric tape. Certopast can be ordered from Kufatec.
Hope it helps. If you decide to install this kit in your A8 D2 please don't hesitate to ask questions.
P.S. In future, if you won't like functionality of comfort blinkers just remove the unit from supplied electrical connector and this will completely restore factory functionality. Stick unit back into connector again and your comfort blinkers will return.