2004 A4 Rear speaker problem

[HadesGrave]

Hi

I have put a new alpine head unit in my A4 in replacement of the concert HU

Front speakers work fine but I cannot get any sound from the rear speakers? has anyone else had this problem and know what to do? and/or have a wiring diagram?

cheers

 

[AndyMac]

The rear speakers have their own amp, so are not connected to the speaker loom (the brown ISO plug). You can get an adapter that will plug into the rear RCA's from the Alpine HU, but I would recommend by passing the amp and wiring the rears straight to the HU as the amp is puny and you have a better & more powerful amp on board the Alpine. Also I have experienced popping when driving an Audi amp with an Aftermarket HU, i.e. everytime you switch from radio to CD, you get this horrible pop as the bodgy capacitors on the amps input circuitry are grounded by the HU.
You will need a couple of ISO speaker plugs (one male, one female) to do this without cutting the Audi loom, as you need to break out the front speakers from the Audi wiring. Audi considerately didn't bother to wire the ISO plug for rear speakers, so 4 of the pins don't exist.
Let me know if you need more info.
Cheers, Andy

 

[HadesGrave]

okay my friend took a look and cut through the loom, i have had an amp and sub installed and alas still not sound from the rear speakers.

after pulling everything out myself i have noticed that the the wires are not even connected. so what do i do run the speakers from my alpine 700w amp or straight from the head unit?