A little history...
My 98 Ram has been having that "not so fresh smell" as of late.... well, since my father does waterleaks on vehicles for a living, I knew that I wasn't gonna be happy to find the source...It was MOSTLY the drivers side, but the passenger side got wet too.
I started with the roof lights I installed......
Nope..... dry as a bone, no water tracks in the dust (best investigative tool you have), no stains in the coresponding back of the headliner.....So, now I have the headliner out and decide I need ot fix that whole I accidently drilled (was in a damn hurry, go figure) and noticed that int eh day light, the head liner was stained PRETTY heavily from water on the back edge.. sO....
I check teh edges and see a few suspect spots on the window seal outside..... I go thru allthe crap of sealing them with black silicone like my father has for almost 30 years.... today... I do water again..... still leaks... I am so pissed that I am ready to call one of the glass guys I have met thru the years (can reccomend a lotta good shops and people in the baltimore,md area) and decide ot take alook at the 3rd brake light to see if the seam is wet if its running in a seam.....
low and behold, the gasket is wet all the way through....I changed bulbs in it when I bought it and the old crushable foam gasket, is permantly flat.... I did a dealer locate and found one nearby which I am getting tommrow.... funny thing is.. Dodge knows its an issue, this part number is the 3rd revision.... obviously arent doing too well..... so if you have a wet floor, keep this in mind...

 

Sweet write up. Great info. I never would have thought about the 3rd brake light.

Thanks for taking the time to write all that.

 

I had the same problem several years ago. The 3rd brake light started leaking after a North Carolina safety inspection where they changed one of the bulbs. A 'cigarette paper' thin coating of RTV on the original gasket around the brake light housing will also seal it up.

It is a hard leak to spot the true source of since a hidden channel in the sheet metal of 2nd gen Ram trucks will carry this water to the passengers side carpet - far from the source in brake light above the rear window.

 

Yep, its very deceiving... I grew up helping doing water leaks.... I woudl have SWORN it was the rear window, since it leaked RIGHT at the corners, night where there is a seam in the room....

 

damn, NOT solved, its bETTER, but not perfect, so, having the back window resealed