my mk 5 h  1.6 twinport  has  started  bringing  the  radiator  fan  on  after  the  engine  has  been  stopped  and  the  key  removed  ,  resulting  in  the  fan  running  the  battery  down .  this  happens  regardless  of  the  length  of  time  the  engine  has  been  running  or  the  engine  temperature  ,  i  replaced  the  coolant  sensor  under  the  ignition  loom  but  made  no  difference  ,  have  had  to  disconnect  the  plug  at  the  bottom  of  the  radiator   when  parking  ,  any  ideas  ,  thanks    

Not entirely sure, but if you have changed the coolant sensor then have a look at the radiator and see if there is another sensor as this may be a thermotime sensor for controlling the fan temperature and run time....although it may be too modern a car to have one but worth checking