Audi A3 rear speaker connections

[Jackson_a3]

Right,

So my rear speakers nor the sub were working, its an 8l facelift A3 non Bose (as far as Im aware) and has a concert headunit. Finally got time to have a quick look today, pulled out the stereo and found this...

Guessing someone has had an aftermarket stereo or amp in the car previously which needed the RCA, and I'm guessing that small blue wire should be going into the back of the headunit??

Because it has been cut, is there any way that I am going to be able to reconnect it or is it game over!? And if I can, where should it be coming from? Got a pretty crap pic of the back of the headunit;

The other end of the RCA and the small blue wire are beneath the back seats at the min so arent plugged in anywhere at that end either...

Any help would be great as sound quality through just the fronts

 

[AndyMac]

More likely they've disconnected the sub at the sub. Have you checked that the red plug is plugged in at the front of the sub (where the speaker is).
The remote is on here:

 

[Jackson_a3]

Andy,you were right,had a ferret about round the sub and found a red connector floatin about not plugged in anywhere. Problem now is i am being completely stupid and cant find where it plugs in!!should i be looking at the bit of the sub nearest the boot or furthest away?any help would be great

 

[AndyMac]

It plugs in here:

Round the front, clipped to the upright part of the enclosure on the other side of the speaker from the cubbyhole