Cooling fans have started operating when they never have before, cool day, hot day, short drive or long, doesn’t matter.  No codes.  Changed the sending unit, no change.  Water and oil temps staying where they should (checked w/ Vagcom).  No one on the RS6 boards seems to have any real idea of how the fans logic works; does the thermostat have a heated element like some of the later VAG engines?  Are the fans operated off an underhood temp sensor?

Should be simple to diagnose but with no codes and seemingly normal operation…