Replacing A6 avant 3rd brake light
 

Hi, just bought -06 A6 Avant. Unfortunately, the auto check informed me that the middle brake light is broken. I went to see and true, the LED brake light is out of order.

Are there any guides how to open the rear hatch interior in order to see what is wrong with the brake light. I would expect that the LEDs are okay, but there might be some bad soldering etc loose wires inside the panel.

Thanks in advance