well my first bugger up was the supplier of the interface loom, who sent me the wrong loom, the non bose loom, i then got the right loom sent, followed the guides on here, but found i had an extra black wire with a hoop connector, which says to me its a grounding wire, so i spliced it to the earth wire identified on the HU wiring sheet, worked fine after that
if you have no sound but power on the unit, it very much seems like the SUB power on isnt working, as i am told the car's sound system needs the sub powered on first before any sound.
When i got the correct loom i wired the sub power on to the HU loom's power line, it worked maybe look up the JVC head unit installation guides for inspiration as it helped me and i was an aircraft avionics engineer!