[andre372]

I've met a minor setback. I have no wiring neither for the ultrasonic sensor or the mirror in the A-pillar connector (I have the black one).

The headlining side of the connector (C0610, black) has the following:

pin 1 (BP - Black/Purple)
pin 3 (B - Black) earth, common for all the different units
pin 6 (PW - Purple/White)
pin 7 (PS - Purple/Slate)

The other side of the connector (C0084, black) has only one additional:

pin 11 - (WRY - White/Red/Yellow)

That doesn't make any sense, according to the "Rear view mirror" diagram, pin 11 should be WY (White/Yellow) and used for the 12V feed to the mirror. The diagram for C0610 (A-pillar) suggests that pin 11 be K (pinK) (well okay, C0084 does show it WRY). Furthermore, the only White/Red/Yellow wire in the A-pillar connector should be pin 9 for the rain sensor ("Wipers and washers" diagram). And that wire, looking at C0961 (rain sensor) should be K (pinK) altogether. C0610 (A-pillar) doesn't list pin 9 at all...

I don't have any intention of retrofitting the rain sensor which would mean changing the windscreen.

For the auto-dimming rear view mirror I would need ("Rear view mirror" diagram):

pin 11 (WY - White/Yellow) 12V feed from F12, shared with the rain sensor
pin 12 (GN - Green/browN) reverse switch

Now, the C0610 (A-pillar plug) layout lists pin 11 as K (pinK) and pin 12 as YU (Yellow/blUe).

The ultrasonic alarm needs:

pin 4 (KY - pinK/Yellow) from BCU's C0660-15
pin 5 (KG - pinK/Green) from BCU's C0660-31

These colours are the same on diagrams "C0610" (A-pillar headlining side), "C0084" (A-pillar other side) and "Anti-theft alarm", but different on "C0359" (ultrasonic sensor plug) which shows the "toblerone" sensor.

Now the really "funny" part. Diagram "Body control unit" confirms that pins 4 and 5 from A-pillar go to pins 15 and 31 of C0660 respectively on the BCU. I took the BCU plug apart and pin 31 was indeed empty. But pin 15 was already occupied by the KY (pinK/Yellow) wire!

I also found 4 pins (19, 22, 51, 52) which are wired but not mentioned in the C0660 layout. I checked all the colour codes and found only a sinlge mismatch: pin 30 marked as LGB (Light Green/Black) is actually PG (Purple/Green). And I discovered pins 7 and 12 which are for the BBUS, are empty. I always thought upgrading to BBUS was plug-and-play (regarding the plug, not the T4 side of things of course).

I don't mind doing the wiring and I'm always looking for the cheaper parts to do some handywork which I really enjoy. But this just drives me crazy. I have a pile of diagrams printed out in front of me on the desk and there's so much contradiction.

At least I have the wiring for illuminated sun visors. I checked the voltage, too, no bad surprises from there, fortunately...