Hi, first time installing any sort of head unit so need some help troubleshooting this issue, any help appreciated. Car is Audi A3 2005, non-bose, rear amplified. New head unit is Sony DAB6650. Using PC9-401 connector. I have removed my Concert and connected up the new HU. The problem is I see nothing at all on the HU display, no sound either. The power connector from the car only has 2 wires, a continuous supply(red wire) and earth(black wire). I've connected the continuous supply(red) to the yellow wire on the new HU and confirmed with a multimeter that there is 12V present even when the ignition is off. I can put a CD into the new HU and I can hear the CD motor going as it takes the CD in. I can press the Eject button and hear the CD motor turning as it spits out the CD. So this sounds like it is getting (some)power but it should start playback when i put the CD in but nothing happens, nothing appears on the display. What I'm wondering is, when I connect the red wire from the car(continuous supply) to the yellow on the new HU, I also have the yellow wire from the car(switched +) going to the red on the new HU. But this connection will have nothing on it since there is no connection in the car to the switched + supply. Do you reckon i need to take the 12V from somewhere and connect it to the red wire of the new HU? There is a link below to the new HU wiring diagram, it might make it clearer. ftp://ftp.vaio-link.com/PUB/MANUALS/CONSUMER/CDX-DAB6650_IG.PDF Any ideas for troubleshooting ?