2012 Audi A8 MMI visible only for a few seconds after screen comes up
 

I have a similar problem that seems to have many answers, which one is right for me? My MMI only displays for a few seconds after the screen rotates up, then goes dark. If I lower the screen then it will do the same thing again when I raise it. I have the 02259 Information Display fault and Control Head (Front) (J685). I bought the Fiber Optic loops to troubleshoot as the optic tester in VCDS does not seem to work for me. I have bypassed all the units I found in the trunk (Amplifier, Backup Camera and one other not sure what it is) with no change in symptoms. All the displays seem to work, in the cluster, plus I can see the backup camera for those brief few seconds when the screen pops up. I believe I need to replace this unit (J685) is this my first step, and can I test this somehow?
I posted this on the ross tech forum and am now searching for a loose wire or micro switch on the display. After spending a better part of the evening pulling out the trim from the dash, I was able to pull the head unit (cd player/sd card reader). The screen is still in the car because of a two wire connection on a ten pin connector doesn't seem to come undone, a youtube video definitely showed that they cut this wire. Anyway in all of my moving around components and wiring now the screen doesn't come on at all. There definitely are micro switches for position of the display. Back at it on Monday.

I'm afraid I can't help you but well done for getting that much of the dash off, can't have been easy.

My mmi screen is doing the same thing on my 2011 A8. The wire connection underneath the mmi display screen is slightly loose. I know this because when I slide in a business card to manipulate the wire the screen flashes on and off. Other owners have had this same problem diagnosed and fixed by the dealer. I will be prying my dash off soon too to see if I can tighten the connection coming into the display. I am interested to see how yours goes, appreciate the pictures too.

https://cimg1.ibsrv.net/gimg/www.aud...a4ab494e80.jpg
https://cimg2.ibsrv.net/gimg/www.aud...9191b417d0.jpg
https://cimg3.ibsrv.net/gimg/www.aud...d048b02931.jpg
So a few pictures on what is going on, first I had to cut what I believe is the power to the display. I couldn't get the cable to pull out. The other two pictures are the micro switches, one for fully raised and the lowered. The full raised switch is broken, you can see the metal tab is missing and can not push the switch. Now that I have gotten this far, I still can't remove the unit because the switches don't have disconnects on them and I don't want to cut anymore wires. I am going to try and bypass the micro switch in a always on position (jump the wires together) and see if it will work this way. I can't really see replacing the micro switch as the unit is very hard to work on in the car.

Turns out it was power to the screen, not sure why. Possible bad wiring, but I couldn't dig far enough to see it. I tapped into another source and solved my problem, sort of. The two micro switches I thought were related to the power issue I couldn't figure out, one is broken so I thought for sure that was the culprit, except it wasn't. So now both switches have been removed, screen works fine. I thought they would control the motor for fully raised or lowered, but it seems to do that just fine without them.https://cimg3.ibsrv.net/gimg/www.aud...208d19026d.jpg
https://cimg4.ibsrv.net/gimg/www.aud...08c07feffb.jpg

I couldn't figure out why I was not getting power to the screen from the original wiring. It was intermittent, so I figured a pulled connection somewhere, I just couldn't dig that far into the dash. I eventually tapped into a hot wire on the passenger side by the fuse panel to power the screen. This works well so far, the screen even without the switches does turn off when it is lowered. As far as the dash I was careful when pulling it apart but still broke a couple of tabs. It went back together fairly easy and everything is solid. Just make sure if you break a tab or bend it that you remove it or straighten it so that it won't foul when you put it back together. There is a youtube video just look for audi a8 MMI display removal, I think it from a 2009 car but still the same, he will show where all the hidden screws are.

Once you have the display removed it is much easier to disconnect the power lead. You can try to repair the lead or buy a used one from ebay and splice it in. The signal wire is the larger diameter coaxial cable (yellow writing in your picture). My power lead had an intermittent connection, so I just jumpered it to another source, Should be a simple fix for you, taking the dash apart was the hard part.