After a week of heavy rains, I just realized my back floor is soaked on the passenger's side. There is dampness under the seat as well, and my trunk is wet. Where is the leak? In the trunk weatherstripping? Back window? Or a hole in the floorboard?

 

Trunk leaks almost always come from the tail lights.
Not sure about the back floor....

 

check the plugs under the back seats.

 

happened to my boys tl as well, its one of the lines inside the car thats suppose to carry it out. ill get more info later, his car is at the dealership with that same problem

 

I have the same problem. But in my car is flowing in from the back right seat belt. It pours out all over the back seat and the cushion part is soaked. I tried taking it apart, and resealing everything thats in there but it didnt help. Im not quite sure where the problem is.

 

For the trunk check the taillights. It usually leaks from there.

Also do you have a sunroof?

 

I do have a sunroof but all my seals are good. No problems there.

 

Its not the seals. Water gets past the seals and there is a channel on all sides of the sunroof that the water flows into and then drains out. There are drains on all four ends of the car that the water flows out of. I know it is a common problem with the 3rd generations that they accumulate dirt up there and the drains get plugged and it leaks into the car. It is common with the 3G because they are older so by now they are most prob plugged unless they were cleaned out. Its possible you have the same prob on yours.

Open your sunroof and pour some water into the channels and see if it flows out. Put a lot of water to make sure. If it starts to pool up then....

 

2 Da Max, I'm interested to hear what happened with your buddy's car. LEt me know.

BTW. My windows or sunroof show absolutely no sign of leaking. Initially I thought there was a hole in my floorboard because the water seemed to have came out of nowhere. But now that I've heard about these drains, I'll look into that. But I have no clue where they're located.

 

This man speaks the truth. The other possibility (if the drain holes are not clogged) is that the tubing might have come seperated. There is a T-fitting under the antenna assembly. The sunroof drain and antenna drain connect at the T and drain out together there... make sure that plumbing is all in place and not clogged/etc.