Third brake light
 

My truck is a 2011 XLT super cab. Has been raining a lot here lately. Opened the back door and found the seat and headliner all wet. Trying to find how the water got in since the back window was closed. Discovered the brake light above the back window full of water. Another common problem apparently I didn't know about. So it seems the replacement gasket is much thicker and will seal out the water. But now the light will not sit flush with the body of the truck. Anyone have to deal with this yet? Your comments would be appreciated.

Not an expert, but instead of a replacement gasket you should have a replacement light with gasket I think. My 2013's was replaced, looked identical to my eye.

I replaced mine with an aftermarket light that had the thicker gasket. I hand tightened it and then went back and did it again about a week later. A third time after several months.

Are you happy with it? Did it leak? I think from what I've found so far the thick gasket is the only one available. Also found a new replacement LED light for just a few dollars more then the gasket.

Replaced mine with a Doorman brand from Amazon,no leaks so far.

I just added some silicon caulking to the original gasket after reading about the issue here. Never had a problem inside the truck, so I'm assuming it is working. I happened to have some clear, bathroom-rated silicon, so it was free for me. I figured if it is rated to handle a shower, it can handle the rain.

That's true, silicon should work. For a temporary fix I used plumbers putty. And so far that has worked. Just don't know how well it will hold up to freezing temps. But it's only to get me through a few days until I get the new gasket or light. Here in NJ it's been raining since April with few days of sunshine.

Here is what I replaced mine with over a year ago. So far so good - https://www.ebay.com/itm/09-14-Ford-....c100148.m2813
The price has gone way up on these now that they are in demand! No leaks. Works great. Looks good. My original gasket was rotting away and my truck has been garaged since I acquired it at 3 years old.

Also a victim of water leaking into the truck. I'm hoping that the problem is the third brake light. Going to order this light as it seems to be a good price and has a large amount of 5 star ratings:
As I was trying to remove the light unit, the lens corners cracked, so I'm going to have to order a replacement immediately.
While standing in the bed, I also noticed that the two rubber seals at the roof gutters were dry rotted and not sealed !? Is this another potential leak and if so, is there a thread that discusses a repair. Thanks in advance, look forward getting this sealed up.

good to see gasket available: