I have a 2007 Murano that developed an awful moldy smell. By pouring water into the sunroof drain holes, and observing that lack of water exiting behind the front passenger tire, I determined that it was the sunroof drain on the passenger side that was the problem. Water was draining into the wheel well inside the vehicle.
Sealing the sunroof with duct tape solved the water problem, but left the sunroof not usable.
Steps I took to fix the issue:
1) I removed the A-pillar trim on the passenger side using a simple pry tool to expose the flexible plastic tube that drains the sunroof water. Easier than expected.
https://www.dropbox.com/s/1tuyv2vrwdzr0 ... o.jpg?dl=0
2) I took a weed-wacker trim line, and fished it down from the sunroof drain hole. I could see that the orange line made it half-way down the tube, and could see that there was no obvious dirt blocking the tube
3) I removed the trim to the right of the glove box using a pry tool and could see the vent and the plastic drain tube behind it. My hands were too small to reach through it to feel where the plastic tub exited the cabin into the engine compartment, but I could see that is where the water is supposed to drain.
https://www.dropbox.com/s/aglk3yj7gi5xi ... r.jpg?dl=0
4) I opened the hood, and removed the plastic trim under the windshied wipers on the passenger side . I reached my hand to feel where it appeared that the tube should be entering the engine compartment. I felt a rubber edged hole, right where is should have been.
https://www.dropbox.com/s/apwb4c85ab5zo ... -.jpg?dl=0
5) I took my orange trimmer line, and fed it through the hole from the engine compartment into the cabin. Looking through the windshield, I could see the orange line under the dash. It was not feeding up the plastic tube. It was obvious that my drain tube had separated from the drain hole into the engine compartment.
https://www.dropbox.com/s/5dwmwuvmdxenl ... t.jpg?dl=0
6) Returning into the passenger seat, I easily pulled the end of the plastic drain tube from where it entered the dash, and saw that in fact, is was draining water inside the car, since it came away so easily.
7) Using a metal hanger, I was able to retrieve the orange trim line that I had fished in from the engine compartment.
8) I used duct tape to attach the orange trim line to the end of the drain tube, making sure it was attached very securely.
9) I returned to the engine compartment, and pulled the orange line and plastic tube back out from the hole, and into the engine compartment. I felt around to make sure the entire end of the plastic tub was penetrating into the engine compartment.
10) I tied the orange trim line to a solid metal bracket in the engine compartment, since there was no way to remove the duct tape from the tube, just in case it happens again.
11) I poured a cup of water into the sunroof drain, and voila, a pool of water poured out on the ground behind the tire.
12) I immediately took some pics and thanked those responsible for the NICOclub forums!
Overall, this was an easy fix, requiring no special tools. A local mechanic quoted me a few (500) hundred bucks to pull everything apart to diagnose and fix the problem. I was able to fix the problem in less than an hour, with zero mechanic skills.