I am trying to install ISO connectors for new audio. The wiring has been messed as this was a taxi. I have 2 brown wires and 1 red/orange wire to connect to red/yellow into HU.  One brown does not connect via the ISO so it's just brown + orange/red. All 3 are permanently live so no switched live anywhere in the wires I have. I have gone back to original taped loom and cannot see that these 3 wires have been interfered with so the switched live may have been made permanent elsewhere in the loom? Is this possible? Is there another solution.

Which colour is supposed to be switched? I checked all the others and none have 12v.

 

The Standard wiring is as follows

 

Pin1 Blue/White Speed signal

Pin 2 Green/Grey Telephone Mute

Pin 3 Grey/White Diagnostic K line

Pin 4 Yellow/Red "S" contact supply  ( 12v any time the key is in the ignition)

Pin 5 Red/White 12v live supply

Pin 6 Grey/Blue Illumination supply

Pin 7 Red/White 12v live supply

Pin 8 Brown Ground

Many thanks I ended up running a new supply from the fuse box and it now works.