[david@a8parts]

For some time now the cornering lights on my W12 have bugged me, they don't operate how the manual says they should, and I had exactly the same problem with my old W12 - I had put this down to the fact that the man who wrote the manual didn't speak to the man who wrote the program for the lights, however after driving Ians 4.2 in the dark, his lights worked just as they should according to the book.

The cornering light should come on in a number of situations: When the steering is turned a reasonable amount (about a quarter turn of the wheel) at speeds below about 35mph, when the indicator is turned on (again at low speeds) and both cornering lights should come on when reverse is selected. This is exactly how Ians 4.2 works (I know I am quoting engine sizes here which may seem irrelevant but bear with me!). My W12 will only illuminate the cornering lights when the steering is turned. It does not put them on when you indicate, nor when you select reverse. This is the same as my previous W12.

After looking into the various modules with Vagcom that could have an effect on the cornering lights the W12 has a different coding in the lighting module to any of the other models of the same age due to the unique headlights with LED day running lights. I tried the same coding as Ian's car in mine but it wasn't happy and wouldn't switch anything on - I also tried a few other (almost plausible) sets of codes and still the headlights wouldn't work. So, my theory is whoever wrote the programming for the W12 set of codes got it wrong and forgot the indicator and reverse settings - I don't know if that is possible, but it seems logical to me.

Any other W12 owners out there able to confirm this, or indeed any other D3 owners with cornering lights able to shed any light on this