Ok, I have everything I need and the full VIN (which I've edited to include). That's one of the last C8s - very nice, I always liked those.
So you do have the RT4 system. Citroen parts don't sell the screen separately for the C8 - the screen is incorporated into the instrument cluster which comes as a complete unit. So the best thing I can think off is searching for a compatible RT4 screen from another PSA vehicle.
I found a few here - but would suggest getting one with as a later manufacturing date to 2008 as possible. There is no guarantee that it will work - but for the £80 £100 price range it is certainly worth a punt. I'm sure you could return it if it doesn't work. Link below:
https://www.ebay.co.uk/sch/i.html?_osac ... n&_sacat=0
The instrument panel is still available from Citroen brand new (Part Number 6103E8) for the sum of: £2357.48! But that does include VAT
So I think you may as well try another screen first. Incidentally did you try the connection from the RT4 Head Unit itself rather than just the one at the screen end?
Another tip - never disconnect the display screen plug without disconnecting the Quad lock connector from the RT4 first - and again connect these up in reverse. The quadlock contains the power source to the screen and connecting these up without disconnecting the power can brick the screens. They can remain active for some time after the engine is switched off.
