My first post, so apologies if I break some rule.
The 3rd break light on my SRT failed, half of it did not light up. Just happened with car in garage over winter.
The 3rd light is unique for the SRT, and can't be bought.
Looked through the forum and found tips and photos on printed circuit boards that are inside the unit, which cant be opened, since it is glued together.

The tip adviced to cut from the inside, through the red plastic to access the soldering joints between the two printed circuits boards, and check the soldering.
So I did, with hesitation. Inside there are two long circuit boards, and there are two wired with power and ground connection between them, soldered at the end of the boards, just as described in the tip I found. The solder joints looked perfect, which at this point was a disappointment. (I work with electronics...so I know good and bad soldering)
Anyway, I took the soldering iron, heated the joints, and then the problem was fixed. Apparently the soldering at this place is a weak spot.
So, I sealed the unit again, and it has now worked for a year.

Very grateful for the tip I found, it is most likely somewhere here in the forum.