I noticed a few days ago...actually it's happened before...moisture in the passenger side floorboard. The top of the floormat is damp. The underside is really soaked. I thought it might be a hole in the bottom of the truck. Checked that and nothing. I can't figure out where it comes from. It seems to only happen when i run the ac/heater. Any ideas where it could come from? Or how to stop it? Thanks

 

Heater core is in the dash right there. you could have sprung a leak

 

I had the same problem. It can be fixed for a few dollars and a little work.

https://dodgeforum.com/forum/3rd-gen...densation.html

 

So it's a leak up under the dash somewhere? It was not raining that day, but it had rained the previous night, so the roads were wet. That's what made me think it might be a hole in the floorboard. I noticed it doing this during the summer, when I ran the AC. I thought it might be the AC sweating, or whatever you want to call that.

 

I also thought it was the A/C, but noticed one day that the floor mat was damp even though I hadn't driven the truck in several weeks. If you want to see the leak in action, remove the wiper arms and the big black plastic piece underneath them. Under the hood on the firewall on the passenger side below the windshield is a big hole through which outside air enters to get into the cabin. If you look inside the hole you'll see part of the HVAC system protruding into the cavity. The gasket around this part is where the water is getting in. Direct a hose onto the windshield so that water drips into the cabin air intake hole (don't squirt the hose directly into the hole) and you'll see water dripping from under the dash onto the floor mat.

 

Thanks for the info. I appreciate it.

 

Just checked your link, makes a **** load of sense... mine does the same thing... I always notice it in the spring, after winter... I'll have to go out and fix that one of these days...

 

Informative thread! I have this happen every so often during rain! Thanks for the heads up. I will have to do this one day :-)

 

Thanks, I had the same problem .

 

I drove around all day with it rainy. When I got home, I looked under my floormat. It was wet under it, but not on the top of it. I also checked and there was no moisture anywhere else under the dash. It was almost like it was sweating. It was cold today and I ran the heater most of the time. Not sure if that has anything to do with it or not.