No sound from rear speakers

[sykopat]

I have an Audi A4 Avant with after market Sony stereo, but I am not seems to be getting any sound coming from rear speakers ??
as soon as connect my original stereo all speakers works as they should ?
I have notice there is separate plug for rears speakers with two white wires, one yellow and one purple wire.
any advice ?

 

[AndyMac]

The rears run off a seperate amp (not sure where it is on the Avant). This amp is pretty abysmal, so although you can get a wiring adapter to hook into it you'll end up with inferior power/SQ and probably associated noise.
You're far better off running new speaker cable front to back (or at least to the amp if you can find it, if you don't want to take the rear doors apart), and wiring the rears directly to the HU. If you don't wanna chop any wires then buy a male & female speaker ISO harness (£4 each from Maplins), join them together for the fronts and leave the rears free for the new speaker cable. This will allow you to plug the front ISO block into the male end, female into the HU and leave the rears accessible.

 

[sykopat]

Thanks Andy !