2006 xc90 2.5 subwoofer install
 

Trying to figure out what speaker wires to tap into for front and rear speakers, no center. Adding a subwoofer under the passanger seat to the amplifier. Trie the 9 volt battery tester to no avail. Attched are photos of the two wiring harnesses. Any thoughts?
https://cimg5.ibsrv.net/gimg/volvofo...55f5f45805.jpg
https://cimg0.ibsrv.net/gimg/volvofo...3465508bfe.jpg

Here's a wiring diagram with the wire colors and speaker designations
https://cimg3.ibsrv.net/gimg/volvofo...f0aad0c2b1.jpg
https://cimg7.ibsrv.net/gimg/volvofo...217c9b5c07.jpg