Dead ICM (Radio) replacement / Aux

[AB Vancouver XC90]

The Head Unit (ICM) on our 2004 xc90 recently died, well actually, it comes on briefly then dies - so I was thinking of somehow replacing it. I prefer the stock look so I’d like to leave the non-working ICM in place, but really want an Aux input so I was wondering whether I couldn’t just leave it there, abandon the underseat amp, and put an inexpensive new 4 channel amp with an Aux (& maybe bluetooth) in the centre console box. A small (ie marine?) amp can possibly be found for under $100, and could be connected to the speaker wire harness under the seat.

I have the High Performance 8 speaker audio and I believe one of the two green wiring harnesses connected to it must contain 4 pairs of speaker output wires (which are later bridged to provide 8 speaker sound). My questions are;

1) Has anybody more experienced than I done this before, and is it as straightforward as it sounds?
2) Is it as just a matter of purchasing a matching wiring harness that I can connect to my amp so I can simply unplug the speaker harness from the amp and plug it into my new amp (harness)?
3) Each of the two green harnesses contain more than 8 speaker wires, so does somebody know what the other wires are? or have a wiring diagram for each connector?

Andrew
’04 XC90, 2.5 Vancouver

[jamadams]

Check the V. drop on the Power and Ground connection at the AMP. this is the large Red and Brown wires.
if there is too much V. drop check the inline connector under the passenger seat.
follow this harness back about 6 inches and you will find another inline connector. this is prone to moisture/corrosion due to close contact with floor and the way too common sun-roof drain leaks filling the floor with water.
Remove the passenger seat-remove the carpet/insulation mat. remove the AMP and find the inline connector under the seat.
check for corrosion.
Picture shows an extreme case.