I had cleaned those recently (before the latest "flooding"), so for my truck at least, they doesn't seem to be the culprit.

 

A quick update, after more than a month. We've had a few heavy rains in the meantime, but there hasn't been any sign of water build-up in the cabin since the repair.

I still have some moisture hanging around the interior (can notice the inside of the windows fogging as the weather cools), so I think I'm going to find some desiccate bags to keep inside to try and clear that up.

 

Cheap desiccant is a bag of white rice. (open, of course)

 

My cab lights have a slight leak. I was thinking about putting a small bead of plummers puddy under them and then tighten them down. Has anyone tried this?

 

I would think only silicone sealant/caulk would be recommended. Plumber's putty likely isn't meant for the temperature extremes a vehicle can see (vs. use on a sink in a house/building).

 

I was thinking that you may not get a good seal with the putty because you could not get enough down-force (pressure) on it, like you could tightening a sink basket and nut.

 

You can get new seals but if the lens is warped it may not seal completely. I haven't got to mine yet but i want to see if they used the same type of material as on the third brake light. May help to use closed cell rubber gasket material for the gaskets as to the cardboard crap the factory used. That will work to seal a warped lens, I used a similar material as a test for the third brake light lens and it seemed to worked well but still experimenting.

 

Subscribed. I've got the same issue on my 96 1500 for the last several years. Will try these fixes and advise of anything else I discover. Thanks to the OP for starting the discussion.

 

Update: I ordered small desicant bags and placed them around the cabin, inside the center armrest storage, and inside the glovebox. All signs of moisture/fogging have now been removed. And, through several rainstorms in the last month, the carpet has remained dry

 

Hit your nearest RV store and buy a roll of putty tape. It's designed to stand up to the elements -- it's the stuff used to seal roof vents and such on RV's.