black/yellow wires go th the thermistor (on the lower right of the oil cooler). they both go to the temp switch (below the terminal board).
is that what you have been testing?
I am showing a black/yellow, orange/red, red/white and brown for the fan and hot light system for a 1999 sportsman 335 from the Polaris shop manual. Do i have the correct model and year of the unit
#31 called a RELAY SOLID STATE LR-60 in the parts fiche, solid state temp switch in the wire diagram. whatever Polaris wants to call it that is the component that is controlling the temp sensor. test the thermistor with a ohm meter to see if it is working correctly.
THERMISTOR RESISTANCE VS. TEMPERATURE
Temperature - Resistance
77 ° F (25° C) - 100KΩ
240 ° F (116° C) - 3.5KΩ
260 ° F (127° C) - 2.5KΩ
290 ° F (143° C) - 1.6KΩ
let me know the results