I know this was an issue in the pre 2015s but thought they had fixed the issue in 2015’s? I have a 2015 and the 3rd brake light is leaking, causing a terrible smell after it rains. Called the dealership to get a new gasket and they only sell the entire house for just shy of $400. I found a few gaskets on Amazon but they don’t have many reviews and the reviews they do have are mixed. Does anyone know of a Ford part number for just the gasket or an aftermarket one that they have used and holds up? Or even an aftermarket brake light that looks very close to OEM?

 

ford never has and probably never will sell the gasket on its own.

 

Firstly, my rule of thumb is I never assume anything has been "fixed" by Ford.

As for the 3rd brake light. I suspect all you will find from Ford is the same gasket/replacement part.

I used to have a 2013. First thing I did was to seal up that third brake light.
I used automotive silicone. Took the light off, ran a bead of the silicone around the top and sides of the light fixture and reapplied it.
Worked great!
I used clear silicone so once cured, you could not tell or see that it was there.