checked the following: both hoses are hot.fan tries to start and stops.jumpered the fan and it ran fine.can I jumper the plug for the radiator sensor? If I can,will it make the fan think it is supposed to be on?

 

Several things to check on this model. Check that fuses/fuse block wiring is ok. Fuse block can be removed to check this out. Plus check the solid state relay and contact pins. There's also a circuit breaker in a sealed pouch on the main harness under the front panel. It can kick on and off,causing problems on fan operation if the contacts are corroded.Just slice the pouch open and you can usually tell real quick. You can get these cheap at any auto store. You can do a resistance reading on the radiator sensor connector when cold,then check when warm. Resistance should drop. These can short out along with the above mentioned items.If needed a Wells SW 526 sensor from any auto supply can be can be substitute.Just cut the wires and splice n you oem connector.If you still have problems tracking down the problem,this cheap manual can really help on eliminating one thing at a time.2009 Polaris Sportsman 500 H.O. Service Manual PDF Download