2012 Sportsman 400/500 and EFI Tractor Service Manual 9923412, Page 382Get this manual
ELECTRICAL Fan Motor Current Draw Test
A current draw test will provide good indication of fan motor conditionA worn or damaged fan motor will draw more current, which causes reduction in blade speed and reduced coolingFan OGBlk OGBlk Connect Ammeter Between OGBlack Pins Fan Harness Brn
Coolant Temperature SensorEFI
The coolant temperature sensor can be tested using an ohmmeterIf the ECT circuit is open, the engine Hot light and fan will both come onWith the engine at an ambient temperature of 68F (20C), disconnect lead and measure the resistance of sensor between the two ECT terminals and compare to the specification listed1With the engine and temperature sensor at room temperature (68F20C), disconnect the harness connector2With the meter in the ohms mode, place the meter leads onto the sensor contacts3Use the TemperatureResistance table to determine if the sensor needs to be replaced
1Disconnect the harness from the coolant sensor (EFI)2Connect DC ammeter in-line on the fan switch harness wiresSee illustration(H.OModelsAn inductive ammeter is required) 3Be sure fan blade is free to rotate4Turn ignition key and engine stop switch to "ON" positionRead the current draw on ammeter with fan running(H.OModelsDirect 12 Vdc to fan required) 5If the fan motor draws more than 10 Amps, replace the motor