I have a 99 GS 300 with about 150,000 miles on it. Several months ago, I noticed that when I took out the rear floor mat on the driver's side to clean it, the carpet was really wet. Just recently I took out the mat again to clean it & again the carpet is wet. I dried it quite well using a wet vac & towels. Last night it rained & thia morning again the floor is soaked. Any suggestions as to find where the leak is?
Thanks

in the 2006+ GS's they said the drain hose was clogged or somehow got moved and it was pouring into the cabin. try getting under your car and looking under the b-pillar (between where your front and rear doors meet). i think this was the solution?

open up your sunroof and clean your drain openings there with some weedwacker cord. If you're still getting water seeping down there its probably due to a dislodged hose and thats no fun trying to fix...

This would the drain hose from the sunroof?

Any information as how to fix it if that is the case (or how to determine if a hose is in fact dislodged?)

In the '06 most commonly that would be the drain hose from the air box under the dash that houses the AC evaporator. The 2006+ has a very weird configuration and the hose often and easily gets clogged, dislogged or disconnected. The hose exits the box and then goes out through the firewall. If it does not drain out though the firewall, then it will drain inside the cabin. The water runs under the carpet and is noticed when it soaks through. There is even a TSB for it:

AC003-07 DEC 07: A/C - Water on Front/Rear Carpets.

steviej

what djspawn said was what i was talking about. i read the same thing somewhere else. like he said, use some kinda thin but sturdy wire or cord and try to unblock it.

I did find the drain holes in the front & ran some trimmer line down through it. The line did stop going in after a few feet. I thought it would just feed through until you saw it underneath the car. Also, I can see no drain holes in the rear of the sunroof area. Am I missing something?

I live in Atlanta and after the recent torrential rains I now have the same problem - a driver's side rear floor that is soaked. I have a 99 GS 300. I located the sunroof front drain holes and one seemed to be plugged so I cleaned it and tested by running water in both the front holes- water drained and came out under the car. However, it just rained again and it seems I'm still getting water. I could not locate the rear holes- how do I get to those? Is it possible the rain is coming in from the A/C to the rear vent under the seat? This is where it seems to get wet. Thank you.