Quad: '00 SP500. 1,000 miles.

Symptom: 99 out of 100 times, the radiator fan kicks on as it should. Everyone once and a while it doesn't. Latest occurrence happened this weekend - rode for 2 hours just fine (fan kicked on dozens of times) and then, suddenly, the OVERHEAT light comes on and and the overflow canister is peeing. Meanwhile the fan is NOT on. Turn quad off, turn key to ON w/ motor off, still no fan. I then let it cool down while cus'ing many times, and decide to limp out to the closest road & the damn thing starts working just fine again - rode another 6 hours w/o a problem!

Now the question is what is wrong? I was thinking a water short, but I rode through dozen of water holes after the overheat w/o any problems. I know the connection where the fan plugs into the harness is OK since I cleaned & sealed it last fall. Could the water temp sensor in the radiator go bad intermittently? Should I replace that? Are those fans known to short if water gets in the wrong place? Maybe a wire shorting to the frame somewhere (unlikely IMO)?

Any ideas?

I was think about just replacing the fan and sensor to be sure to rule them out, but at the price Polaris wants, I'd go broke. I also ordered a Quadovator fan override to hopefully give me a 'plan b' if it should happen again, but if the problem is the fan or wiring to the fan, that isn't going to help.

Just curious if anyone here has seen similar problems in that era SPs. Was hoping this is a known problem?

 

Did you check your wireing because if its not your wireing than I do not know what happend

 

sounds like it would be a connection problem. i would pull all the connections apart to check and clean and regrease them to rule it out. i would doubt that a fan or the sensor would go bad off and on. just my .02

 

What electrical connections are there that I should trace?

I would assume that the two power fan wires goto the ECM? Or is there a relay? The radiator temp sensor also goes to the ECM? Where is the ECM located on this bike?

I'm also 1/2 tempted to cut the plug adapters between the electrical harness and rad fan - and then solder & heat shrink tube them just to be sure. The oem plug is kinda iffy. I also need to check to see if the Quadovator mod will bypass the ECM & any relays... just t make sure if I have power and the fan works, the fan will spin.

 

corrosion in the temp sensor connector or if the coolant level doesnt come in contact with the sensor it wont trip the fan is the coolant level low? just an idea

 

as far as i know there isnt an emc of that yr 500. just cdi box and coils and a recifier. it would not have anything to do w/ that part i beleave. just my guess. trace the wires to make sure power is getting thru and any connections that might have corroded over time.