THE STANDARD BRASS SENSOR MOUNTS ON THE OUTFLFOW PORT OF THE RADIATOR UNDER THE RUBBER HOSE.   iF YOUR OUTFLOW IS PLASITC DO NOT USE THIS SENSOR.   DO NOT MOUNT ON THE RADIATOR INFLOW OR YOUR FAN WILL RUN AT HIGH RPM ALL THE TIME.a
 
THIS SENSOR IS INCLUDED WITH THE PURCHASE OF A CONTROLLER
AND NOT INCLUDED IF YOU PURCHASE ONE OF THE OTHER  SENSORS.
 
 IF YOU HAVE S PLASTIC OUTFLOW PORT, THIS SENSOR WILL NOT WORK.