Porsche Cayenne 2004-2010 and VW Touareg 2003-2010 instrument clusters with MFT (color) display has many electronic problems. Easy, but expensive dashboard repair solution - exchange all instrument cluster. But you can try repair cluster – this will cost less.
We found few most common instrument cluster defects:

-          No central LCD or speedometer/tachometer scale illumination – possibly illumination high voltage transformer is defective - check this link;

-          Central cluster LCD illumination is ok, but no picture or picture is not stable – blinking. Possibly you must exchange LCD display – check here;

-          Central cluster LCD illumination is ok, picture is stable, but on LCD screen is white, red, vertical/horizontal lines. This is possible LCD display water damage. In this case exchange only LCD glass;