Premium sound wiring

[SamE30e]

Alright, so I got a new headunit and ran new wires to the front speakers, and I don't really want to run new wire to the back for the rears.

I have a 87 325e with the premium sound setup, there is a factory amp in the trunk and it has the fader above the radio. I pretty much want to use existing wires to get to the rears if someone could help that'd be awesome

Thanks.

[Jordan]

Run new wire.

[DaveSmed]

Simple enough. Cut the fader plug off, and chuck it and the solid blue and solid yellow wire in the trash.

Connect the yellow/black wire to the green/black wire from the headunit.
Connect the yellow/red wire to the green wire from the headunit.
Connect the blue/black wire to the purple/black wire from the headunit.
Connect the blue/red wire to the purple wire from the headunit.

Now go to the connector for the factory amp, unplug it and cut these wires:

Two black/brown wires
Black/purple
Black/white
Yellow/black
Yellow/red
Blue/black
Blue/red

Connect the black/purple to yellow/black.
Connect the black/white to blue/red.
Now temporarily connect a black/brown wire to the yellow/red wire and turn on the headunit. If sound comes from the left speaker, make the connection permanent, and connect the other black/brown wire to the blue/black wire. If there is no sound, reverse the black/brown wires.

[SamE30e]

Simple enough. Cut the fader plug off, and chuck it and the solid blue and solid yellow wire in the trash.

Connect the yellow/black wire to the green/black wire from the headunit.
Connect the yellow/red wire to the green wire from the headunit.
Connect the blue/black wire to the purple/black wire from the headunit.
Connect the blue/red wire to the purple wire from the headunit.

Now go to the connector for the factory amp, unplug it and cut these wires:

Two black/brown wires
Black/purple
Black/white
Yellow/black
Yellow/red
Blue/black
Blue/red

Connect the black/purple to yellow/black.
Connect the black/white to blue/red.
Now temporarily connect a black/brown wire to the yellow/red wire and turn on the headunit. If sound comes from the left speaker, make the connection permanent, and connect the other black/brown wire to the blue/black wire. If there is no sound, reverse the black/brown wires.

Yea I tried that myself before you posted it using diagrams. I just said fuck it and went and bought 60' of wire, connectors and heat shrink tube. I lost the sound from my tweeters but oh well I'll wire em up later.