Hi Stuch, just wondering if you'd had a response. My Overland is doing the same.
Found this post on the 2014 Grand Cherokee information -Australia thread, post #4606.
re: the climate control dual zone issue. Ours was fine for a week or so and then it went a bit haywire. Mentioned it to the service department of our dealership and we are now tracking it and will report back to them.
Try this to correct it.
Press Synch Off
Take drivers side all the way to HI
Take passengers side all the way to HI
Let blow for 10-20 secs.
Take drivers side all the way to LO
Take passengers side all the way to LO
Let blow for 10-20 secs
Take drivers side to normal temp that you want (ie: for us 19 degrees)
Take passengers side to same temp
Press Synch On
See how you go.
It corrected it for us, but the service department wants to know if it goes out again so we are keeping an eye on it.