Re: So I get my leather dash replaced then I notice this...
I don't have condensation in my Jeep, but I did have this problem with my previous car, a 2003 Murano. It ended up being a pinhole leak in the seal around the cargo hatch window.
I knew that it was in the rear because I was seeing water on the cargo hatch rubber mat after it rained hard. I would also see condensation on the rear window and the front window once the sun came out. I took a squirt bottle full of water and sprayed around the seal from multiple angles. I was finally able to see where it was dripping. It wasn't much, just enough to allow moisture in. Because of this, the drip didn't start immediately after applying water, it took 20 to 30 seconds for it to build up enough moisture to start dripping.
I first filled in the area with Permatex silicone. This didn't fix the leak. I ended up pulling the silicone off and re-sealing, using the silicone, all along the top edge of the hatch window. This finally fixed the leak. It ended up that the leak was entering one section, traveling sideways, and exiting another section inside the car.
If you are still getting condensation, I would suggest doing a water test around the rear hatch window. A squirt bottle or garden hose should do. Just make sure to hit it from different angles.
2014 Jeep Grand Cherokee Limited 4x4 3.6L v6 Billet Silver, Black leather interior (new)
x 2003 Nissan Murano SE AWD 3.5L v6 Sunlit Copper, Black leather interior (new)
x 1995 Ford Mustang 3.8L v6 Automatic Silver, Red cloth interior (used)
x 1986 Mercury Lynx 1.9L 4cyl Manual 3-door Hatchback white, grey cloth interior (used)