My mother turned started the Cayenne on a really cold day and within seconds she said she heard a pop, the radio/nav screen shut off, and now no heat comes out the vents feeding the back seats. The dealer has looked at it twice and cannot figure out what is causing this. Interestingly, cold air will blow out of the vents when the AC is on, but it's been a few months and the heat back there still doesn't work. Since the dealer is basically scratching their head on this issue, any advice? Anyone experienced the same problem?

 

I have the same "no heat" in the rear - I just thought it was design flaw

 

It's unfortunate. I hope someone has heard of this problem because my dealer has already replaced some various parts and we're still out of luck.