I've got an '04 Cayenne S and the car thinks the rear door is always open, when it isn't. The rear windshield wiper also does not work, though the rear break light does and the washer fluid nozzle functions, though I imagine the pump likely isn't there. I'm really at a loss about this one.

 

Hm, that is an interesting one. My guess is that there is a microswitch inside the door latch assembly that isn't triggering the light to go off. I've never taken apart a rear latch assembly before though. Wiper is probably the motor or a bad connection. There should be a wiring harness connector to the rear door assembly somewhere, you might take that apart and look for corrosion in the pins which could be causing some issues.

 

I guess i've got some taking apart to do. I've also just noticed my left rear window switch only raises the window, but won't lower it? Wow electrical gremlins all at once...

 

you can take it to the showrrom