How to tap VSS for aftermarket stereo?

[RS4Per]

Hi All,
I've been ripping my hair out most of the day trying to figure this one out. Anyone have some pointers? According to my best interpretation of Bentley, I should be hooking into the black/red wire on the Green instrument cluster connector, which should be the VSS signal. Alas, after connecting into it and testing with my head unit (Pioneer Avic-8100nex) it still says no speed signal detected.

TIA,
Per

[Rick_RS4]

its pin 3 connector B

http://i184.photobucket.com/albums/x222 ... g~original

[RS4Per]

Thanks! So, to make sure I'm clear: that's the back of an RNS-E you linked to, and since I have an aftermarket head unit I need to find that Connector B that used to go into it?

Thanks again,
Per

[RS4Per]

Digging in the dash, this is the only OEM harness I see available at this point. I checked out the blue connector pin 3, but it doesn't have a wire in it.
EDIT: seems like the connector is some type of aftermarket piece that allows the OEM harness to be adapted to an aftermarket stereo (the first aftermarket system was put in by an installer. The other side of the connector, not pictured, is supplying power / ignition, etc. to the HU).

I can see the three connectors that plug into it (pictured) are part of the car's harness. But the fact remains: there's no wire going into pin 3 on the blue connector which seems to be Connector B. Thoughts?



Again, thanks for your help.

-Per

[RS4Per]

I'll keep having a convo with myself for now ...and share what I'm learning on the 'do this via the instrument cluster path' which is the one I was exploring earlier. ...happy to get it going in whichever way, though.

So, Bentley says (as picture above shows): speed going into instrument cluster is off of green 32-pin connector (T32a), pin 22. And that wire should be black/red (SW/RO ...German abbreviations).

Confirming via my connector:


A vampire tap into that wire, connect to the head unit....and still says no speed signal . Running out of ideas.
Rick - happy to hear more thoughts from you re the other connectors.

Thanks,
Per

[Rick_RS4]

you need to buy a ''repair wire'' small

then put it in the plug in pin 3 on the blue plug

[RS4Per]

Thanks again, Rick.

Logically, I don't quite follow, though. The blue plug is part of the car's wiring harness. If I add a repair wire into it, and then - presumably - hook up the other end to the after market HU ( ? ), how will that add the necessary speed signal? I'm sure I'm missing something here.

Edit: wait - too many blue plugs: are we talking about the one behind the HU, or the one that connects into the instrument cluster? (My comment above was if we're talking about the one behind the HU).

Thanks,
Per

[RS4Per]

I just checked the blue connector that plugs into the instrument cluster (in case that's the one we're talking about). It has a pin and wire in position 3 already.

[RS4Per]

Putting the pieces together, I think I have it... I need to add a repair wire into the green instrument cluster connector on either pin 6 or 21. Here's why I think that's right, and again - happy to be proven wrong!

I found this in a B6/7 thread on Audiworld http://www.audiworld.com/forums/s4-b6-b ... me-2549205 which shows the green connector pins 6 and 21 being 'speedo out'.


Then the last post in this thread, http://tech.bentleypublishers.com/messa ... eID=200885 states,: "While the B7's use of the CAN buss is expanded over the B6, the execution of the design is basically the same. That being the case, there is no logical reason the auxiliary speed data output is not available at the instrument cluster. As I provided in a reply to your other post, investigate the presense of the needed speed signal from the instrument cluster at the GREEN 32 pin connector. Check Pins T32a/21 wht/blu and T32a/6 with the frequency function of a Multifuntion Volt/Ohm Meter".

That's in line with the AW post, i.e. 6 and 21 are the supposed speed out signals.

Finally, both my 6 and 21 pins on the green connector are currently vacant, so this seems like something to try?

Cheers,
Per

[RS4Per]

And - - nope. Tried both of those pins and each time HU says no speed signal.
Unless anyone else has an idea, I think this is about the only thing that would get the job done: http://www.autotoys.com/x/product.php?productid=10366

Thanks for the pointers, and Rick - if you have some clarification on your idea above, I'd appreciate hearing it.

-Per