What brand of fan? Spal is what Polaris uses.Spal Electric Fans - The Fan Man https://webstore.spalusa.com/en-us/p...rcycleatv.aspx Plus did you reuse your old fan connector and you have it correctly oriented as far as the fan ground and hot wire? Just sniffing around..

 

Replacement fan was an All ***** Racing A12-701004 that I purchased at Royal Distributing as a direct OEM replacement. It came with proper plug on it so wiring wasn't changed. I appreciate the interest you are taking in digging into this. I am at a complete loss where to go next.

 

Jump the fan directly to the battery and see if it operates ok. Plus the manual has an amperage test on fans. If it draws more amperage than the oem,could be the problem,plus fan wires resistance fluctuating when you touch the blade doesn't sound right. Try the amperage load test.

1. Disconnect the harness from the fan motor.
2. Connect a DC ammeter in between the fan switch
harness wires
3. Verify fan is free to rotate. Turn ignition key and
engine stop switch to “ON” position. Read the
current draw on ammeter with fan running.
4. If the fan motor draws more than 8.8 Amps,
replace the motor.
Fan Motor Current Draw:
Less Than 8.8 Amps

 

Thanks. I'll give it a try. Fan works OK but not sure about amperage draw.

 

I will chime in with perhaps totally useless information, but here goes:

Did you test that new thermostat? Take it out and drop it in a pan of boiling water, it should open. Run it under cold water and it should close. Tstats (even car ones) have notoriously high DOA rates. It's worth a shot...I replaced everything on my Sportsman 400 BEFORE I tested the tsat, and found the tstat was defective.

Good luck, my overheating was VERY frustrating.