Ok, so the leak gremblin has finally found me! I've had my truck interior out for a bit due to me doing a sound damping installation. Well the last 2 days we've had tons of rain. Last night i went to go do some more work in the garage, and noticed the passanger rear corner, right near the vent was wet. I started trying to figure out where this slight water was coming from...thought maybe it came in the vent or something. BUT then i started looking a little higher. There is an area right behind the canister for the airbags that has some ply fill bating stuff up in there...when i stuck my fingers up there to check..sure enough...it was wet....but the wierd thing is anythign above this area...is dry...i cant find any residue of water. Could it actually be the 3rd brake light? and it channels its way around the rear glass and then into this area? I would never have known of this small leak if i didnt have the panels and carpet out.

In the pic where its cirlced red, is where the batting is stuffed in. thats where i noticed more water due to the fact the batting was holding it

 

I got the leak now too. After 9 or 10 inches of rain in 3 days and 23K miles I guess that was all it could take. Rear brake light is the suspect for me. Entire rear ceiling was damp and most water collected on the driver side rear seat. Oh well, still under warranty and back to the dealer I go.

 

It seems as though all the dealer does is replace your 3rd brake light, and gasket with the exact one that comes from the factory. this will only fix the problem for a time being again. I choose not to tke it to the dealer, but rather take the 3rd brake light off myself, and add a new thicker CCF (closed cell foam) gasket that I made. No problems ever since!!!

 

My 3rd brake light started leaking last weak. Ford fixed the leak and replaced the headliner as it was stained.

 

I put on a smoked third brake light this week and had some of that butyl rubber stuff (Also known as Dum Dum by body shops - stuff used to water proof spoilers to decklids, etc) and put that on the light as I see how the gasket gets squished and you can see how it will leak eventually.

I haven't found a leak yet but hopefully this may help someone else.