Factory amp bypass

[McFly8484]

so I'm trying to install subs in 2011 a4b8 and now only passenger side door and the dash speakers are working ....what the hell did i do and can i just bypass the factory amp without a wiring harness also where would a good spot be to find my factory remote amp wire or where I can tap into one ?

Thanks in advance

[A4x]

First of all, which factory system do you have? Concert or B&O?

Assuming Concert, the head unit sends a low level signal to the back right corner of the trunk where the amp is located. The amp takes this low level signal from the HU and sends out a speaker level signal to the doors and center channel in the dash.

The low level/input wires are thinner (pins 23-32) and the high level/output wires are thicker (pins 3-20).

Here is a diagram:



You should unplug the factory subwoofer at the subwoofer and just leave that plug hanging. This will turn off the factory sub. Just reach up, pinch the connector, and unplug it.

For a remote wire, look at the fuses in the passenger side of the trunk. You can tap into one for remote, I forget which one. Just look at the list of fuses and use your head.

[Smac770]

Concert and B&O are not parallel terms.

First is which front end do you have, CAN bus infotainment (Chorus/Concert/Symphony) or MOST bus infotainment (MMI, 3G High in the case of North America MY11 B8)?
Second is which sound system do you have, 4 speaker Basic, 8 speaker Basic Plus, 10 speaker Standard, or 14 speaker B&O? If you have a subwoofer on the rear deck (sedan) or under the spare tire (wagon), you have standard or B&O. If you have 1" circles that say Bang & Olufsen on them on the side mirror mounts, then you have B&O.

There's a different electronics setup for every one of the infotainment + sound system combinations, so no point speculating until you clarify the system involved.