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Discussion Starter #1
My cooling fan turns on with the ignition and stays on 100 percent of the time. I have found that the temp sensor on the back of the rad is not plugged into anything. Can this be why the fan is always turning on ? This has been an issue since I bought the atv and I don't know where I would plug it into. Some help would be greatly appreciated
 

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The wires have been disconnected from the sensor and are jumped together near there. Means sensor wasn't closing and fan wasn't coming on. Someone did a bush fix and never made proper fix.
 

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Discussion Starter #3
Ok so here is a pic of the pig tail from the sensor behind it is the wireing to the fan it's coming off the headligh cables how do I properly wire this what do I need
 

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This should help.

Mark
 

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Okay thank you for the electrical schematic, I have found both the Orange/Black & the Red/Black wires as they are directly wired together bypassing the temp sensor which makes sense why the fan is on 100 percent of time, Now what is the name of the part or piece that plugs into the temp sensor pigtail, I presume this will have the 2 wires so the power is routed through the temp sensor first before the fan it also shows on there there is a 10A circuit breaker I'm wondering this comes as one piece or unit or if not can I use and general fuse inline on that wire. I just cant find what im looking for on any parts website. Any help locating this piece would be greatly appreciated
 

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Okay thank you for the electrical schematic, I have found both the Orange/Black & the Red/Black wires as they are directly wired together bypassing the temp sensor which makes sense why the fan is on 100 percent of time, Now what is the name of the part or piece that plugs into the temp sensor pigtail, I presume this will have the 2 wires so the power is routed through the temp sensor first before the fan it also shows on there there is a 10A circuit breaker I'm wondering this comes as one piece or unit or if not can I use and general fuse inline on that wire. I just cant find what im looking for on any parts website. Any help locating this piece would be greatly appreciated
Thermal Sensor... take a look here @ the "Polaris Parts Fiche", under "Cooling System". Link: http://parts.polarisind.com/Assemblies.asp

The "breaker" is a separate component in the fuse block, located under the front fender.

Item # 21....

 

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Discussion Starter #7
Yes i was able to find the temp sensor item #21 but i can't find where to order the circuit breaker and pig tail housing that the temp sensor plugs into.
 

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Discussion Starter #9
Ok finally found time to get this sensor installed. I looked at wireing schematic and the previous owner indeed bypassed the temp sensor and the fan was wired directly that is why the fan was on 100 percent of the time. So I installed the temp sensor wired it up and ran the atv to test and the fan never turned on. Rad fluid starting spitting out over flow. I removed wires and bypassed temp sensor and fan turns on. My questions is could I have faulty temp sensor. Could there be air in rad system. Looking for input. The atv never over heated prior I just don't want to
Burn out a 300 fan running it 24 / 7
 

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Ok finally found time to get this sensor installed. I looked at wireing schematic and the previous owner indeed bypassed the temp sensor and the fan was wired directly that is why the fan was on 100 percent of the time. So I installed the temp sensor wired it up and ran the atv to test and the fan never turned on. Rad fluid starting spitting out over flow. I removed wires and bypassed temp sensor and fan turns on. My questions is could I have faulty temp sensor. Could there be air in rad system. Looking for input. The atv never over heated prior I just don't want to
Burn out a 300 fan running it 24 / 7
Yup you have a bad temp sensor.
 

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Discussion Starter #11
Ok the supplier I bought previous temp sensor off is sending me a replacement. Is there a way I can do a boil test with the new sensor and a multi meter. If someone could lee me know which settings to use on multi meter and at what temp this switch should complete the circuit to turn on the fan. I would rather test new sensor prior to putting in machine first
 

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Discussion Starter #12
I received the new sensor installed it and same problem Fan would not come on. Is there anything else that could cause this or is it the fact I bought a cheap eBay sensor and I have to fork out the cash to get one from Polaris??
 

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Discussion Starter #13
Just posting another update I ordered the oem part from Polaris and the fan still didn't come on when I ran the engine. The rad definetly got hot, is there anything else that could cause this thermostat or water pump. I'm all out of ideas the fan works hard wired and atv doesn't overheat but with fan temp sensor wired in the fan doesn't come on at all and the atv will over heat
 

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does the bike have a second sensor on the left of cylinder with 1 wire only? Its called a thermistor sensor.
 

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Discussion Starter #16
Would the thermistor stop the fan from coming on thought if I bypass the therma sensor the fan works but with the temp sensor wired up the fan never comes on this is the 2nd sensor i have gotten
 

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i have a bike here with same issue, new thermal sensor and thermostat but fan still wont come on, my dealer said it is possible its the thermistor, i know someone who might have a used one, ill try different thermistor. They are expensive parts to swap brand new, ! i dont have alot of time to work on it as we ride our new bikes every weekend.
 

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Discussion Starter #18
Even if the fan works hard wired in and the only thing separating the wires is the temp sensor it could be thermistor. could it be the rad fluid is not getting hot enough where the temp sensors is being the pump or even the rad cap
 

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Discussion Starter #19
Ok I have tested the thermistor and the rad temp sensor both work as they are supposed to. So there is no electrical
Issue. Could the thermostat be faulty even if the rad gets really hot, I have not tested the this yet. I also read on another post if the rad fluid is bubbling out of overflow bottle the head gasket could be the issue I do not have any rad fluid in my oil what would be any other signs to look for to rule out head gasket.
 

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Not sure about your model, but make sure the water pump is primed and actually moving coolant. Fan won't come on if there is no coolant flowing across the sensor to read temps from. Had this problem on my 2004 500 ho. Once I got it primed the fan would come on and the engine no longer overheated.
 
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