It's a question of parts compatibility.
Your J527 unit seems to be the culprit for the horn not working with the
'New' (different platform) model of MFSW buttons you want to install (which includes the J453 unit).
The
Scirocco 2009 Model Year is a
deep mess because within the 2009 Model Year itself VW made changes to the parts.
Some Images:
- J527 separated from the slip ring (>> 11/2/2009)
https://es.aliexpress.com/item/1005004904832844.html
- J453.
https://es.aliexpress.com/item/1005002091961091.html
or,
https://es.aliexpress.com/i/1005001930049856.html
with,
https://es.aliexpress.com/item/1005005951938973.html
- J527 built in the slip ring. (same MY)
https://es.aliexpress.com/i/1005004523046503.html
...and now comes the fun part, the original VW diagrams, where the precision to define this amalgam of parts is conspicuous by its absence.
That is,
only by doing readings with diagnostic tools and with some experience is it possible to know how the parts involved work, the diagrams are only interpretive.
...as we saw in previous post:
1-For models without multifunction steering wheel. Basic equipment. We could say that it is applicable to all Model Years.
with G85 ⬇ (for connection purposes, it is the same as the previous diagram)
2-For models with multifunction steering wheel. (
'9' MY)
3-For models with multifunction steering wheel. (
'A' Model Year, etc)
T12/9 =
LIN, not 'can'.
T12/8 = GRA.
Compare '9' with 'A, etc' and draw your own conclusions.
...and now you say that it is strange, that in other Scirocco it works and in 'yours' 2009 it doesn't work, etc...
Have you tried a
three-ground airbag with three-ground wiring with blue/white wire through pin T12/8? I imagine that it is the only possibility you have to work your horn with those NEW buttons (J453 'lin'), although it is possible that if 'your' J527 detects MFSW it will try to make the horn work through that 'can' T12/9... and the horn will not work.
IMHO, VW should have waited to launch the VW Scirocco on sale in 2010...
You can too throw your Scirocco in the trash, and buy one of those thousands of ID3s that VW has stored in infinite fields and that I think VW is going to sell in China at Aliespress prices, that is, for a third of northern European prices. The opinion of the ID3 prices for southern Europeans is this =
.