Aftermarket HU install...pac audio...and I'm and stuck stuck STUCK!
 

2007 A4 2.0T Quattro, symphony, non-nav, non-bose

I ordered the PAC audio C2R-AUDI - which supposedly keeps all the factory stuff the same (except the steering wheel controls).

Anyways, I wired up the pac audio adapter to my Kenwood DDX616 and I have no rear speakers or sub. Checked, double-check, and checked again my wiring connections but still nothing. I'm at a loss here. I've spend hours searching with no luck. PAC audio instructions are sub-par.

Anyone experience this problem? Stock radio says symphony, 6-disc changer - How do i know if I have a factory installed amp?!

I'm hitting a brick wall here...any help would be greatly...HUGELY...appreciated!

Did you ever figure this? I've run into the same issue and also not sure hiw to connect the steering wheel controls with the pac steering wheel adapter I have.

Same problem
 

I'm having the same problem. Bought the car last week 08 2.0t a4 s-line. I didn't put a aftermarket radio in, but was messing with the fader ad come to find out the rear speakers don't work. I found a compartment in the trunk but all that's in there is the Sirius box and no amp. I was also reason else where that previous owner of vehicles may have had an aftermarket radio and forgot to plug a cord to the factory radio when trading the car. Unless there is another compartment in the trunk for an amp, and it's not Bose. I've looked on YouTube and no videos, which is surprising because I've heard of this issue a lot.

this thread is old, but if you guys still need help, check out crutchfield.com
i have always used them for radio shit and looked into this same idea but left it alone because it was too expensive. they should be able to easily help

I'm also at a dead end rear speakers not working and don't know what fuse to tap for ignition to the aftermarket stereo any help be highly appreciate