RADIADER FAN HAS A PLUG IN WIRE IT COMES ON WHEN IT NEEDS TO TO HELP COOL THE BIKE LIKE WHEN SITTING AT STOPLIHGTS ESPECIALLY WHEN ITS HOT OUT IF NOT WORKING AT ALL CHECK FAN FUES IF NOT BLOWN THE FAN IS NO GOOD ALSO YOU CAN CHECK IT BY PUTTING A HOT WIRE FROM THE BATTERY TO ITS HOT AND THE NEGATIVE TO THE NEGATIVE BUT UNPLUG IT FROM THE HARNESS FIRST AND IF THE FAN RUNS YOU HAVE A SHORT SOMEWHERE