Carpet damp in rear

I was vacuuming my 07 CM yesterday and noticed the carpet in the rear was wet. I have the Weather Tech liners both front and rear and it only seems to happen in the rear. I'm guessing that he exhaust runs right under the mats and the heat generated by the exhaust is going up through the floor and since the mat offers no way for the heat to easily escape, you get condensation build up between the floor and mat. Anyone have this happen, and better yet what can be done about it? Right now it's a PITA but I pull up the mats and let it dry overnight only to repeat the scenario the next day.

 

I would check for a leak around the rear window or 3rd brake light. I have never heard of exhaust causing anything like that.

 

Second vote for rear window leak.

My previous truck started having water in the cab, looked all over and finally found it was the back cab window.

Had it removed and re-sealed to fix.

Get to it before you get mold and mildew in your cab.

Good luck!

 

Ok I will start there. Never thought of the 3rd brake light.

 

Ok on further inspection, the wet spot is in the middle of the floor under the mat, with no other water anywhere around it. The floor mat has a wet spot right in the middle (underside) and that's where the carpet is damp. We have not had rain for days. I'm at a total loss. I guess the next step is to put some towels down first and then put the mat on top of it. Maybe it will raise the mat enough to allow the carpet to breathe. I hope this goes away during the winter, because I can see a smelly problem developing if not. There is no other water anywhere in the truck.

 

Do you have an antenna or a sunroof on the roof? Check those areas, too...

 

In the center, how close to the console? Been running AC a lot? Maybe some sort of leak/ condensation from rear AC vents/ duct lines in/ under center console? Just throwing out ideas... .

 

Right in the foot well on both driver and passenger side. The transmission hump area is dry. I'm wondering if there is a heat shield that has disintegrated or something of that nature, allowing more warm air to rise against the floor and transmit into the cab. It's condensing under the mat, I'm sure, because I took the mats out today and had to run an errand it was about 30 miles. When I came home the floor was bone dry. I rarely run my A/C, maybe once or twice per year just to keep everything lubricated.

 

Floor vents from under front seats blow right there in that area. Does it happen if your don't run the floor vents at all? Just spitballin' here.

 

Yes it happens when I am not running the heat/cool system at all.

 

Any odor in the cab? Meanwhile, consider pulling the affected mat, drop in a couple of spacers about 1/4 inch thick (got an old yardstick laying around? They're free at some stores...) Run the spacers side-to-side; objective is to slightly vent that portion of the floor/mat. Let us know what happens...

 

That's a good idea Tmac. I'll try it today and let you know what happens. There is no odor in the cab, luckily.