I recently purchased a 2000 polaris sportsman 500 h.o.

The first day I took it out for a ride I went about 10 minutes before the engine temperature light came on and I began to boil over out the reservoir.

What I have done:

The wiring harness that runs down the front two low beam lights and the fan connection wasnt showing any power at all. The lights I could careless about atm so I ran the fan directly to the battery using a fuse.

The fan is on full time now when riding, however I wasnt getting any power after what seemed like 15-18mph. Every time I gave it throttle past this point it would feel like it bogged down a bit and just wasn't getting the juice needed. My dad figured that the coolant wasn't cycling through the block properly due to the thermostat (Which we tested, and it worekd) and decided to take the thermostat out temporarily. This actually seemed to resolve the issue, the fan cooled the motor, circulated fluid properly, and gave us power back, however only up to around 45 mph before it wanted to bog down again. (this caused issues with hills)

Thermostat is good, rad cap is good, restored power back to the front switch where the fan and lights plug in, still fan won't toggle on and off.

I personally have no idea about anything like this and are simply trying to relay the issues for my dad.

About to test the sensor, about to take the rad out. Please advise if you have any suggestions! Everything and all appreciated!

 

Welcome! Most of the times when the fan doesn't cycle on it's cause by a shorted out radiator sensor(4010161) $48 at Cycle Parts Warehouse OR you can try to match it up at any auto store and splice your harness into it. Make sure you leave the radiator cap off,jack the front end of the atv up and run until the fan cycles on and off to purge any trapped air. Make sure the regulator/rectifier wires are plugged in securely(located behind the radiator and bad about wires coming loose) and charging 13.5 to 14.5 volts back to the battery. OPT