Audinecromancer

Long story short i decided to do something different with my newest B5 to me. Im adding in a double din touch screen in this one and im wishing to isolate the rear foglight switch function to power up a reverse camera instead. Ive so far found that i need to make it its own 12v ignition source to the grey and blue stripe wire as to have function any time key is on. It looks like this car has a module? To turn on rear light? If anyone has info to help this idea ive cooked up id greatly apprechiate it. Only one im familliar with was my 97 A4 pre face lift and this one seems much different. Im not finding a wire on the switch i can tap into to get a signal with the rear fog lights being on to run to the head units camera trigger switch ( wire that would come on if you were to out in reverse.)