A3 2011, no base and rear speakers working, NON Bose

[br2021]

Hi I have a A3 Sline 2011 3 door. I have the chorus double din and everything was fine till a little while ago i noticed i wasnt getting any Bass. I have now checked and im not getting any sound out of my rear speakers. I have seen a number of threads about swapping the head unit and im looking to go to halfords and just get them to install a new HU. What i dont want is the rear speakers to still not be working. Can anyone tell me if this is just a HU issue, i have looked for the AMP and i cant find it, I have a 3 door and the amp is not in the rear wheel arches so im not sure where it is or how to test what might be the issue.
I have attached a number of photos of the HU and harness so you can see what im working with, all help is appreciated.
Cheers

 

[NHN]

Most chorus units are fitted with fronts only, needs rears fitted, I'd say, done it number of times.

 

[br2021]

Most chorus units are fitted with fronts only, needs rears fitted, I'd say, done it number of times.

So your saying theres no rear speakers?

Any ideas about why theres no base?

Thanks

 

[NHN]

Bass or Bose, no bass cause its got no sub & no bose as it has no rear speakers or amp or sub.

Rear speakers can be fitted, but depends how far you want to go.

 

[br2021]

Bass or Bose, no bass cause its got no sub & no bose as it has no rear speakers or amp or sub.

Rear speakers can be fitted, but depends how far you want to go.

No BASS, it definetly used to have a BASS, but now you can only hear change when you adjust the treble or the MID

 

[DR.AUDI]

No BASS, it definetly used to have a BASS, but now you can only hear change when you adjust the treble or the MID

Hi mate did you get to the bottom of it in the end?
I replaced the same chorus unit from my 2011 a3 8p 5 door (non-BOSE) today with an Xtrons MA80A3AL and noticed the rear speakers no longer working.
Xtrons referred me to this link https://bbs.xtrons.com/viewtopic.php?t=61 but i'm struggling to decipher their instructions.
I believe the last portion suggests I should remove a few crimped wires from the head unit harness and replace with wires that I run from the rear speakers?
One issue is that they show a different connector to my a3 quadlock harness. I have the exact same connector including vacant pins as the one in your photos.
I've also found the HU wire diagram but not sure if its of any use to my problem.
Also does wire no. 13 AMP-CON need to be wired up somehow to power rear amp?
I would be grateful if someone can point me in the right direction.

 

[DR.AUDI]

Most chorus units are fitted with fronts only, needs rears fitted, I'd say, done it number of times.

I re-fitted my chorus unit earlier to rule out the xtrons wiring and I'm embarrassed to admit that you were right.
There was no audio coming from the rear even with OE Chorus HU.
I though It was best to follow up so as to not mislead anyone.
Its strange that the rear door cards have the speaker grills on them and not some kind of blanking plastic...