A3 8P No Sound from speakers (factory bose)

[Stev_A3]

Hi, please could somebody help me. I have a 2006 A3 with the full Bose system from new. I changed the double DIN (cassette) to a single DIN pioneer unit by halfords.

It worked an absolute treat for two months with no problems apart from a minute 'engine interference' you can hear at low volume. This is caused by the amp?

Halfords recommended that they fit a suppressor instead of a ground loom wire. This caused me to have no sound whatsoever so they removed it instantly and blamed a fuse in the engine bay.

So far:
I have had a proffesional check the system wiring at the headunit and he found no faults
No faults with headunit as halfords tryed unit in a staff car
A different pioneer headunit was fitted and still no sound

Audi told me the original needs to be in for them to diagnose.

Is there a simple cure to get sound again?

Thanks

 

[Stev_A3]

*I now have sound through a pioneer deh-s720DAB - However:
Rear speakers not working
Heavy interference from engine and speakers crackling.

What do you recommend? Halfords are against a suppressor for my car as this is what caused the fault originally.

 

[Stev_A3]

To confirm the parts I needed 100% are:

CT24AU09
CT27AA08 Aerial Adaptor
CTSAD008.2

This is for a 2006 full bose system. Truly sounds amazing now, no interference.