I have at least 3 speakers not working in my L322 but I can't be bothered taking the door cards off and scoping the inputs to see if it's the amp or not. :)
I'd suggest trying the phone module as that's been messed with. You should be able to see a light in the fibre and a light in the module where the fibre goes. The fibre with the light goes in the module connection without the light.
ok. I think fibre B is too long for that position and someone has been messing to bypass the TV module.
If you can remove B from the plug and put it in C, then put A where B was C will then go into the TV module and Bobs your whatsit.
Looks like you have connected it up wrong, all you have done is looped the in to the out. Have you got a better picture that shows where the white fibres go?
If you look at @Blob pic you can see how some of them route,
The green and brown plugs are the aerials and probably coax. The black plug are the fibres.
What's the part number for the TV unit as not all are compatible ?