3rd brake light working but weak

[Danny Scott]

The 3rd brake light in my tailgate is very dim when I put the brakes on, only just shows, but all the leds are emiting some light so it is sort of working?!

Cant work out how to gain access to it if anyone can help or has any ideas?

 

[-Ju-]

My mate just bought an A3 with the same problem. He replaced it with a new light unit from Audi for about £40, job done.