2007 Polaris sportsman 450 cooling issues

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Jan 20, 2018 | 06:05 PM

Powerstrokin704

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2007 Polaris sportsman 450 cooling issues

I have recently acquired a 07 sportsman 450. I've read a lot of forums that talked about a thermal switch on the radiator but I can't seem find one. But besides that I've unplugged the thermalcouple on the side of the block and the fan does come on. Does this lead me back to the ecm or is there something else I could possibly check?

Jan 20, 2018 | 06:21 PM

old polaris tech

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From: North Texas

No sensor on the radiator as the thermal sensor on the head sends the signal to the ecm for the fan to kick on. The ecm module also controls the hot light,contains the regulator/rectifier for keeping the battery charged,battery protection circuits,auxiliary power control along with having solid state circuit breakers enclosed. The fan should kick on as a default if you pull the thermal sensor plug.Item#10 on the breakdown. If the fan isn't kicking on then it's possible an ecm problems,but I'd check out the sensor also. Have the sensor test on the 500 but not sure if it's the same sensor without checking.General test is to check ohms when cold,drop sensor in hot water and ohms should decrease to complete the circuit to send to the ecm.
THERMISTOR READING DURING OPERATION
Condition Approx. Reading
(Min--Max)
Temperature
Hot Light
On
178Ω -- 190Ω 215° F
(102° C)
Fan Off 296Ω -- 316Ω 180° F (82° C)
Fan On 236Ω -- 251Ω 195° F (91° C)
DON'T take these readings as gospel.. The manual for your year model will have the correct tests.http://www.recrepairinfo.com/product...-manual-p-2917

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