Back passenger floor is wet

[mberlin]

I think I've figured out what the problem is, just not sure how to fix it. I've had a problem with water in the front passenger floor before. That turned out to be a clogged sunroof drain tube. I've been pretty good at keeping that clear. But now the water is in the back passenger floor. From what I've read on this site and other Volvo sites, I'm thinking it probably a clogged ac drain tube. I've taken out the front passenger seat to vacuum out the water in the back floor. Not sure if it will ever be totally dry but am drying it out as best I can. But before I put everything back, I need to fix the problem. How do I find the ac drain tube? Does anyone have another ideas about what might be causing the problem? Thanks in advance.