Focus mk3 Titanium Sony radio, lcd and facia Inop. Every since battery went dead the whole audio system has went down.  Inc lcd screen(bvc) audio head unit and the fiam Facia control panel.  I am getting a constant 12v supply to the unit plug and obviously checked for fusing , all good.  Has anyone came across all 3 units packing in at the same time?

Did you try to jump start the car before the battery replacement?  I've only ever seen all 3 fail once after a spike from a welder, but I guess it's possible a similar spike could occur from a jump.

Have you checked every single fuse for continuity?  I know you said there's a 12v feed but just in case there's an additional fuse for those items?

Cheers Tom. Yes. I checked and replaced fuses( me being me). There are 3 under the glove box and 2 in the boot fuse box which relate to audio, radio etc. F67 is sync multi function display, F79 radio, touch screen etc also does hazards and door locks ( which work) , and fuse f85 which mentions radio. Tbh I have checked continuity with my trusty light probe. And checked all fuses only 1 popped under bonnet box which was the heated screenwash jets. TBA later  lol.  

So battery was flat, pressed the start button and all lights started flickering like crazy inside car, got my trusty noco booster pack, connected live first and earth last , switched on and car started.  Everything works apart from stereo,  lcd screen and fascia, ( been dealing with batteries for a  long time) 😒 changed out battery and tried unplugging and various tests to no avail. There is deffo 12v to main plug for head unit.  Without bench testing won't know 100%,   but I can't be bothered, so bought a new android 10 system. See what  happens next week.😁 I'm just one of those that when something doesn't work I need to know why!!🤣

So there we have it, sony system completely dead. Installed the xtrons android system and works a treat and  sounds much better than the stock system.