Hey everyone,



I've done extensive research on this particular issue that I am experiencing and unfortunately have not been able to find a resolution for it yet. I'm hoping someone here may be able to provide some further insight into my problem.



Background:

I have a 98 or 99, unsure of which year tbh, Polaris Sportsman 335 that I am fixing up for my wife as a first ATV to get her into riding. I purchased the machine for her a few years ago and it needed a little bit of work at the time, but has since set outside for a year or so and has caused more issues. Recently, I started working on it again to revive it for her. Prior to it sitting outside, the hot temp light did not come on and was working as intended. After sitting outside and pressure washing the machine in preparation to work on it, the hot temperature light is constantly on. After doing research, I've found that it basically boils down to either the thermistor sensor inside of the radiator or the LR60 fan control/solid state relay module under the "hood" of the machine.



My first troubleshooting step was to verify that the fan would come on with direct 12volts and it did. Initially I was certain that the LR60 module must've went bad from sitting out in the weather or after I pressure washed it because I crossed the two black/yellow leads coming off of the thermistor and the fan did NOT kick on. Fortunately enough, I have a parts machine that I am able to swap parts out with. I grabbed the LR60 module from the parts machine and replaced it on the machine I was working on. I immediately tested to see if the fan would come on after swapping the LR60 module out and it DID kick on. I thought to myself, "Great! That's totally what it was!". I was wrong. The hot temperature light was still on.



After this, I pulled the thermistor from the parts machine and swapped it out thinking, "Okay, this has certainly got to be it, right?" Nope. Hot temperature light was still on. After swapping the thermistor out, I checked the resistance on both of them to see if they were working properly. Neither of the thermistors were reading the correct resistance at room temperature - one read 300k ohms and the other was bouncing all over the place. I thought to myself, "Alright, so the thermistor is bad and that's what's causing the hot oil light to come on." So, I couldn't find a new thermistor for sale that directly fit a 98/98 model Sportsman 335.... so I ordered a new thermistor for a 2000 model 335 (Yes, I know they are different style plugs, but the resistance readings are the same - I modified it to fit the older style connector). After verifying that the new thermistor was reading the correct resistance and decreased with temperature increase, I swapped it out and checked to see if the temperature light was out. Nope! The dang thing was still on!



So then I began chasing the wires coming from the hot temperature light itself to see if there were any breaks in the wire or if the connectors were corroded or something. There was one wire break on the red/white white at the terminal block itself, so I replaced the connector and fixed that issue. I thought, "Okay, so with a brand new thermistor that is definitely working correctly and with a swapped LR60 module that seems to be functioning correctly, this broken connector has to be the issue." Nope. That didn't fix it, hot temp light still on!



As a final thought, I wanted to test to see if the LR60 itself was also reading the input from the thermistor and doing what it was supposed to do in regards to temperature.... so I started the ATV and then let it come up to operating temperature with the leads disconnected from the thermistor. After warming the ATV up for about 15 minutes, the operating temperature never really got low enough to trigger the fan to come on. Per the manual, the fan will come on at 260 degrees fahrenheit, or 2519 ohms ± 3%. At this point, I wanted to force the machine to get hot enough to trigger the fan to come on to ensure that it was working, so I took a propane torch and gently and slowly heated up the oil cooler around the thermistor as I watched the resistance with a multimeter. After I got the resistance to read less than 2500 ohms, I plugged the thermistor leads back into the LR60 module and viola! The fan came on. Big sigh of relief at this point. This tells me that the LR60 is doing what it is supposed to do and reading the temperature from the new thermistor and telling the fan to turn on. I then pushed the temperature up hot enough to trigger the hot light at 290 degrees Fahrenheit, or 1607 ohms ± 3% hoping that maybe there was a stuck switch or something inside of the LR60 module but was still unable to get the light to trigger off.



I'm ecstatic that the fan is actually coming on like it's supposed to and will keep the machine cool if it does ever start to overheat, but at this point, that dang hot temperature light is invading my nightmares and is driving me insane. Why won't it go off!?!?!?



PLEASE HELP!!!!