I know this has been discussed in the passed in other threads across this forum and they all usually lead to the sunroof drain being clogged! but this doesn't seem to be the case for me and I'm kinda stuck and don't know how to solve this issue. My car is an MY05 S60 with the sunroof if that helps.
Three weeks ago after a heavy storm I noticed my passenger footwell carpet was wet (it looked like it leaked from the top right of the passenger footwell on to my rubber mat) and my rubber floor mat had water on it. The first thing that came to my mind was the dreaded sunroof drain was clogged So I brought my car to my mechanic who took an air compressor with a hose to clear the clog and I thought that solved the issue but it didn't After another rain fall I noticed again that my carpet on the passenger side was wet (same place mentioned above) and my rubber floor mat had water on it. So I thought that my mechanic didn't unclog it properly so I decided to try unclogging it myself but before doing that I wanted to confirm that it was indeed the sunroof drain that was the culprit, so I bought 3/8 transparent tube and used a funnel to test the drain. I emptied about one liter of water and all of it was emptied on the pavement behind the passenger front wheel and there was no water in the footwell so that points to the sunroof drain not being clogged. So my next test was the drain in the windshield cowl on the right side, again emptied about one liter of water and it drain under the car with no sign of water in the passenger footwell. At this point I have no idea where the water is coming from and decided to remove the passenger carpet and see whats going on behind it. When removing the carpet I noticed only part of the carpet had a water stain on it which was the top right and bottom right of it, so it seems to be coming from just where the glove box ends under the dash. So I don't know what do to next, for now I have the carpet removed and will be waiting the next time it rains to keep an eye on where the water is coming from. If anyone has experienced a similar issue and solved it please let me know what caused your leak!