So, I think I've figured it out
To update the topic and maybe help others ill share my findings.
So I had a Pre facelift A3 8V with the beige headliner and "normal" controls. I bought a 2015 LED unit (see photo below).
note: I bought one with the sunroof but my A3 doesnt have that option. Doesnt matter as the button will be there but purpose no function.
I tried it by just plugging in the connectors. Unfortunatly nothing happend. At first I thought I needed to connect the rear lights aswell to create some kind of electrical circuit but that didn't help either. I then went and took the unit out of the car and checked the wire that comes from the car and goes into the LED unit (the 6 pins connector). I made a photo (see below).
I remembered the ElsaWin posts in this topic so I booted up my own Elsa and checked the differences (see below).
Variation 1:
This is the pinout for the wire that goes into the unit when you have the "normal" unit, mostly found in the beige units and NON LED units. In ElsaWin this connector is indicated as "T6am".
PIN 1 = Brown
PIN2 = Green
PIN 3 = N/A
PIN 4 = White/Purple
PIN 5 = Grey/White
PIN 6 = N/A
Variation 2:
As you can see this is for the LED unit as the 12PIN connector to the rear interior light is on this one. The wire that goes into the unit from the car is indicated as "T6d".
PIN 1 = Grey/Purple
PIN 2 = Green
PIN 3 = Brown
PIN 4 = Blue/Red
PIN 5 = Purple/White
PIN 6 = Grey/White
This means that the LED units has 2 more cables coming in. I then looked at what all the wires in the connectors are for.
Variation 1:
PIN 1 = Brown goes into '367'. That is the GND (ground).
PIN 2 = Green goes into 'J519'. That is the BCM (body control module) that controls electronics in your car.
PIN 3 = N/A
PIN 4 = Purple/White goes into 'B467'.
PIN 5 = Grey/White goes into 'B731'.
PIN 6 = N/A
Variation 2:
PIN 1 = Grey/Purple goes into line 'B316'. This is a Positive connection (30amps) in main wiring harness.
PIN 2 = Green goes into 'J519'. That is the BCM (body control module) that controls electronics in your car.
PIN 3 = Brown goes into '367'. That is the GND (ground).
PIN 4 = Blue/Red goes into 'T8a'.
PIN 5 = Purple/White goes into 'B467'
PIN 6 = Grey/White goes into 'B731'.
So the final rewire I need to do is;
PIN 1 =
PIN 2 = Green
PIN 3 = Brown
PIN 4 =
PIN 5 = Purple/White
PIN 6 = Grey/White
This means I "miss" 2 wires.
- Blue/Red goes into 'T8a'.
- Grey/Purple goes into line 'B316'. This is a Positive connection (30amps) in main wiring harness.
I assume the Grey/Purple one is needed for constant power to the unit and the Blue/Red to control the sunroof button. Meaning I will need to run a cable to the fusebox (location SC8) for a permanent +12V. Hope anybody can confirm this.
Sorry for the long post, hope anybody can make use of it
.