fblonk

Hi,

We have a 2014 RX 350, and I keep getting moisture on the passenger floor on the flat portion only. If the floor mat is left in, it will have moisture under it. I have cleaned out the sunroof tubes, and I have blown out the Air condition condensation drain tube (it drips very well) and I have checked where the tube goes into the AC plenum and the tube is on all the way. I do not get water on the carpet where it elevates to under the dash, the carpet is dry there. We had a bit of a cold front here, so the AC was off and the carpet dried. It then rained and the carpet stayed dry. This leads me to believe it is coming from the air conditioning. When the a/c goes back on, we have moisture. I have cleaned the cabin air filter, and looked under the vehicle and do not see any damage or missing parts. I have owned Lexus (the LS line mostly) for almost 20 years, and I do most of my own work (former tech). I am looking for any assistance on this. I am ready to remove the air condition condensation tube, but when the a/c is on, it drips very well. I do not see any obvious water track marks and do not relish removing the passenger side and look under the carpet for track marks where water is, as it may not even be coming from under. Any thing I have missed? Any help is greatly appreciated.

Aegean

Try to dry it and then go to a car wash a couple of times without using the AC. At least you will know if it is from outside like a passenger door leak. If no water then as you suspected somehow the AC condensation reaches the floor.

fblonk

We had a pretty hard rain one night after the carpet dried and no intrusion. Carpet was dry. I can't figure this out...

MattRX

If that doesn't work, try cleaning the sunroof drains. You'll need to open sunroof and pour hot water down the drain holes. Even better if you can get a tube and compressed air to shoot down them. This was on a Toyota Matrix but I assume the procedure would be almost identical.

Clutchless

The passenger side sunroof drain may have come apart somewhere between the floor and the roof.
I had this happen years ago on a Honda.

salimshah

One of the reason can be the condensate from the A/C. With high humidity there is a lot of condensation. It should drain through a pipe. The shell of the heat exchanger can have a bad seal and that causes wetness in the passenger side carpet. The fix is very elaborate and expensive.

Check the easy things first.

Salim

smknkeyz

Any rips in the passenger door seal? If it's only happening after car washes/driving conditions, then it may be water intrusion from a torn or damaged seal. Good luck!

fblonk

Thanks for the replies! I have cleaned out the sunroof drain tubes with weed whacker line and while they were a little dirty, no issue. I also used a small rubber line and fed water into the sunroof tubes and they drained fine. I did recondition all the seals on all the doors, sunroof and rear gate. I also cleaned the meeting points of where the seals meet the body everywhere.. I do not think there is water intrusion from the outside (rain) as much as I suspect the a/c condensation. I blew out the a/c tube again this morning, and the carper has been dry (we took out the passengers floor mat and have it in the back) I told the wife to leave the mat out and use the a/c and I will check it in the morning. I will keep you informed. Chime in if I missed anything as I am still scratching my head...

Ftime

When I fixed my sisters plugged sunroof drain, 2014 RX450h I thought it was still leaking because the carpet kept getting damp after drying it with a fan all day in the summer. Turned out it was so soaked the water wicked into the insulation under the carpet all over and it never dried out completely. I pulled up the carpet and insulation as far as I could in the front, propped it up and ran a fan under it for a week every night. Then she kept the carpet pulled up for another week and brought it back for me to put back together. All good after that. As a side note that electrical junction box on the right, under the carpet was soaked too. She had a few random error lights on her dash, on too with the BSM mirror light always on. I blew out all the water, disconnected the wire plugs, blew the sockets and wires off too. Then sprayed electrical contact cleaner, blew them out again and all the lights went out. Also, I remember doing our RX plugs and coil packs seeing some rubber plugs (I think) on the firewall on the passenger side after I removed the wiper assembly and tray and all that crap to get to the plugs. Might be another spot to check? I hope it isn't too bad, good luck!

JTinDC

Were you able to find a solution to this problem?

fblonk

So, the tube where the condensation line goes to the evaporator case was pulled away, just a bit and that is where the leak was coming from. I secured the tube. No more leaks.

Thanks to all that commented. Much appreciated.

Biblegeek

I’m having the exact same issue with my 2012. What is involved with securing the tube? I blew it out from underneath the car. Can you access it from underneath? Anything need to be removed?

fblonk

I just looked where the tube goes through the firewall from the inside and I saw the tube was a little loose. It should fit snug, mine did. No securing needed.

Biblegeek

where? Inside of what?

JTinDC

Thanks for all your replies. Did you need to remove the glove box or things of that nature or do you just stick your head under the dashboard and there it is?