GPS and radio out how to fix 2004 CT
 

I have a 2004 Cayenne turbo. The stereo and GPS screen is completely dark, no sound. I have not found a helpful thread. The old ones say they have had theirs go in and out and no solutions. Mine is just out. I have checked all the fuses including the one in the stereo and have even replaced them with no solution. I may try to replace it with a used unit but they are hard to find. How do you test the unit itself or fix?

I had the guys at short Circuit in San Jose CA take a hard look at mine a few years ago. Porsche won't give them schematics or let them order parts. The only fix is to have Porsche sell you a rebuilt. Price was around $1200. Used ones on Ebay go for about the same, but I won't buy either of them at that price as I've had two fail.

I took the $1200 and upgraded to an aftermarket system and now I get iPod and Satellite integration. I also found an adapter for about $100 that interfaces with the factory speaker wiring so I save the hassle of running new wires and didn't have to cut into the factory harness.

I haven't checked in a while, but if the factory head end unit could be had for $200 - $400 I might be inclined to replace it instead.

I am curious to know if you are able to control the aftermarket head unit with the steering wheel buttons.

I know this is an old post, but ill tell what we did on my 04 Turbo with full optic setup.
I installed the new Alpine X801 U 8" unit. We jsshopped for a box that connected to the steeringwheel and now controles sound and back and forth. Mute and the other buttons dont respond.

So there are units to buy specificly for this car with steeringwheel addons