Does anyone know the route for the fibre optics in the MOST system, I have a 2007 Vogue with the blank screen and orange flashing power button, I have signal at the IHU, the cd player and the touch screen, I have checked the female fibre optic connector in the rear and it has no led in the fibre optic, is there something between the iHU, the touch screen and the cd player, before it then gets to the female connector in the rear?
The facelift have an audio controller under the passenger or drivers seat, mine doesn’t have that, someone said there may be something in the centre console but I’m reluctant to start ripping that apart until I can find out more,
Cheers

The Most signal runs in the following order
1 IHU
2 Touch Screen Display
3 CD Player
4 SDARS Receiver (if fitted)
5 Bluetooth Module
6 TV Tuner (if fitted)
7 Rear Seat Entertainment Module (if fitted)
8 TMC Tuner
9 Amplifier
10 Back to IHU

Here's a post from when I solved the problem on my car

Audio Problems solved useful information Report post
I recently purchased a 2006 L322. I knew when i purchased it that the radio did not work. The system was displaying the Land Rover logo and the orange light was flashing.

Research on here led me to believe it was the Bluetooth Module, so before investing in a new module I bought a fibre optic loop byepass, fitted it to the fibre optic plug going into the Bluetooth Module. The logo was still the same and the orange light was still flashing.

So I booked the car into a garage that specialised in Land Rovers and Range Rovers for diagnosis, they told me it was the TV module. I purchased a used TV module, it did not make any difference.

The car was subsequently booked into a Vehicle Electrics speciailist. They diagnosed the Harmo Kardon Logic 7 Amp, I purchased a replacement and fitted it and it did not solve the problem

My Icarsoft scanner was still saying it was a fibre optic fault so over the last few days I have taken the various components out and checked the Most Circuit starting with the Integrated Head Unit, the Touch screen display, the CD Changer and then the various components in the boot

All checks appeared to show the problem was with the CD Changer as the red light went into the CD changer but did not appear in the boot area. As the plug into the back of the CD Changer incorporates the power lead my fibre optic bypass loop would not fit. I therefore took the fibre optic cables out and connected them together with a piece of tube.

This showed that the red light now appeared in the boot area so I could discount a broken fibre optic cable.

I re-connected the fibre optic cables and plugged it back into the CD changer and once again there was no red light going into the boot.

The CD changer had been changed in the past as the car is a 2006 and the CD changer had a manufacturing date of 2015 on it, and it did power up when the power plug was plugged in so I did not think it was the CD unit that was the problem

After researching online and finding no answers i thought I would try removing the fibre optic cables from the CD Changer plug and swapping them over.

I fitted the power/fibre optic plug in the back of the CD changer after swapping the fibre optic leads over, turned the ignition on and hey presto, the radio came on !!! RESULT!!

Everything now works, radio, CD Sat Nav, Reversing Camera and Venture cam

Cheers for the info bud,
The issue I have, is that I have a light from the IHU but nothing to the cd player, if I fit a loop to the optical lead for the touch screen, I get the light at the cd player, connect the cd player and I get the light in the boot, just can’t get it past the touch screen,

Try reversing the most cables at the touch screen. if that does not work it looks like the touch screen could be faulty, try substituting one that is known to work and see if it solves the problem. As you have already proved that bypassing the touch screen gets the most light through to the boot, the touch screen or the way the most cables are connected to it are your problem

yeah that is next on my list, someone sent me the wiring diagram for the touch screen and it shows which fibre optic cable is the input and output, so will check that, i now have 4 screens (long story) 2 of which i know are working, so definitely not a faulty screen, i did wonder if one of the modules in the boot was hard wired to the touch screen, like the amp and the screen isn't allowing the signal through due to that, the previous owner replaced the amp but that wasn't the original fault as the touch screens power light wouldn't come on before, ended up being the IHU, so maybe the amp fitted is now faulty, just need to strip out the rest of the rear trim so i can get access to the amp and maybe swap that out and try again, i just hope i can remember the sequence for the optical cable harness when it all goes back in!

I did find this online, it was an AI answer to whether a faulty amp would still allow an optical signal to the rear modules, but it would explain my issue:
No, with a faulty amplifier (amp) in an L322 Range Rover, the optical signal may not reach the rear entertainment modules. The amp is part of the MOST system, and a faulty amp can disrupt the entire system, including the transmission of signals to the rear modules.