Do you have the Driver Assistance package where the button is on your stalk? It looks like a car in between two white lines. If you don't have that, but have the camera behind your rearview mirror, you can use ODBeleven or VCDS to enable the function. But it will be on constantly. You won't have a button to turn it off instantly, unless you retrofit the column with the button stalk.

@@KZfaqpoiuytre I press the button on the lights stalk but nothing happens on my 6 month old A3