I have my brothers 04 Sportsman 500 I need to replace the cooling sensor that is in the bottom of the radiator. I have 2 dealers by me and they can only come up with the one in the top of the radiator the parts guys cant find any that are in the bottom. They even ran the VIN to make sure I had the correct info. The one that they have looks the same but the pigtail is way to short and for $75.00 I will not cut and splice wires. The one tech said he has seen them on the bottom before but never had to change one. Thoughts thanks.

 

Here's what some members have reported using. Have to use you old connector. Buy Wells Vehicle Electronics Cooling Fan Switch SW526 at Advance Auto Parts

 

Looks like it might work. It might be easier to cut and splice at that price but not at $75.00. I'm not sure that's the problem I cleaned up all of the connections and I ohmed out the sensor and it now opens and closes so maybe just a bad connection. I will keep an eye on it. Thanks for the info.

 

The sensor ohms resistance must drop when hot to complete the ground path circuit for the fan. One thing people over look also is there is a 10 amp fan circuit breaker under the front panel.If it's terminals are corroded/shorted out and doesn't have power on each side of the breaker red wire,the fan won't kick on either.Item #1. Dirt Cheap Yamaha, Honda, Arctic Cat & Polaris OEM Parts & Accessories – Cycle Parts Warehouse

 

If your OEM sensor is a 4010161. Then any sensor for a 84-88 Nissan Maxama or 86-89 Nissan Stanza will work.
Here is a few.

Napa FS147
Wells SW526
Blue Streak TS-127.

I,m using the Blue streak and a friend of mines uses the Wells.

 

TLC that is the part # but the wire is about 8 inches short. OPT when I have the ohm meter on it when its cold I have no reading (open) when it heats up the ohm meter goes to 0.00 (like my GPA). It's not plugged into the other end from the breaker to the fan during the ohm test. So now I know that when it gets hot it lets the power flow thru the sensor and to the fan. I did replace 3 breakers as they looked like (well you know) ch!t.

 

You can jump the fan motor itself to eliminate it as a problem first.You can splice the new sensor into the old harness if the wiring is too short..But sounds like the sensor is operating as it should be open when cold and gradually closes when warm.It just operates like an on/off switch in completing the ground path. Red/white power wire on sensor harness connector goes through the circuit breaker first.Look at the schematic diagram on your model.Index of /ORV Manuals/Polaris/Sportsman/2004 PS may have told you wrong on the sensor harness.. one side of the sensor harness should be hot from the circuit breaker,when the sensor closes,it passes power to the hot wire side of the fan. The fan is already grounded by the brown wire..

 

The sensor only has two back wires and you have to spice your old connection on anyways , just cut the wire further back or spice any wire to it for more length.

Have you eliminated the fan being the problem? Just jump a 12v source to the two fan wires and see if it spins.
If you ever need a new fan buy it directly from "SPAL" for $80 rather then the dealer for $300 for the same Spal made fan.