I have seen lots of helpful posts and information floating around on this site. Lots of good folks. Hopefully I can get some assistance with an issue myself. Thanks in advance!

I have a 2009 Polaris Sportsman 500 HO. The fan never comes on. The machine overheats when riding slow or in low gear and even when overheating the fan does not come on. I assume there's enough air moving when fast riding that you don't need the fan. I have replaced the fan and temperature sensor in the radiator and both seem to be functioning properly. (The fan runs perfectly when I give it 12 volts and when the machine is overheating, I tested the resistance in the connection for the temperature sensor and the switch is open, no resistance). These are the only two parts I could find here that may be bad and causing my problem. In talking with a Polaris dealer, this was also the only suggestion he had. The dealer stated that there is no relay that controls the fan. I checked and tested all the fuses in the fuse panel in the front of the machine. As you can tell, I'm at the end of my rope with it. Short of taking it to a dealer and paying them 100 bucks an hour to diagnose and fix it (which was their recdomendation) I don't know what to do next. Any help or guidance would be greatly appreciated.

 

Trapped air can cause most of the problems along with a dirty radiator.Jack the front end up,tires off the ground a little and leave the radiator cap off. Let it idle and also open the small bleed screw on the water pump housing to help remove trapped air pockets.Squeezing hoses can help to remove air also. If the hot light comes on before the fan does,the radiator may be dirty especially at the back around the fan area. Some have had to remove the radiator to thoroughly clean it.

 

The fan doesn't come on at all. Ever. That's my problem. If it came on and just wasn't cooling off I'd understand I guess. But the fan should come on when it gets hot regardless right?

 

Fan should come on but if it's an aftermarket sensor it may trigger at a hotter temp than the oem sensor. Plus looking at the 2009 parts break down,doesn't show radiator sensor,just the sensor on the head. Sure of the year model,not an efi machine?? Sorry does show the radiator sensor but shows it in the electrical parts.http://www.partzilla.com/parts/detai...P-4010808.html Again do you have the oem sensor or an after market one?

 

Think I may have this figured out( I hope). The relay supplies power to the fan, the relay receives it's power from a 20 amp circuit breaker on the main harness.This may be the problem if it's corroded. Should be strapped to the harness above the relay. It must have power on each side of the red wire. If not,slice the pouch open and check for corrosion.cheap to replace at any auto supply. Items 5 and 12 on the wiring diagram.

 

Ding ding. Old Polaris tech got it. It's actually a 10 amp circuit. But that was it. I took it out and jumped it with a 10 amp blade fuse and the fan comes right on no problem. Also in that cooling system diagram the radiator sensor is # 18. The one on the engine is just for the light in the dash.

 

Also. FYI. Polaris told me more than once over the phone that there was no in line fuse or breaker. So there's that. Just for anyone else who runs across this and thinks it doesn't apply to them because they were told they didn't have it.

 

Once in a while I get lucky. Starting to forget more and more as the years go by. Yes all the fan sensors had a 10 amp breaker. 20 amp breakers were reserved as the main breaker on earlier models..

 

Well thanks again. I greatly appreciate it. I don't have enough spare hair to be pulling it out over this thing haha.

 

Have to admit this 2009 model was different than most of the other carb models.Unless you have gone through a lot of wiring schematics you can over look this breaker. When I saw the relay I started looking for the breaker that I knew had to be there. Hope your problems solved.