SO, on my 2004 330 ATP, I've never heard the oil cooler fan run until last night. We broke it all down to do a carb clean. During a break, I unplugged the fan and hooked it directly to a hot power source and the fan kicked right on. We started tracing wires etc and have narrowed it down to the fan not being grounded. I feel pretty sure that it's the orange/black wire running from the fan up to the ECM. I've read some of the ECM recall stuff and I don't recall ever receiving a notice (the shop I bought the machine was pretty shady and prolly didn't submit the paperwork properly). My question is, that are your thoughts on just making the fan come on with the ignition and run full time? My concern in battery life... will it maintain charge?

Thanks for the input and I look frowrd to your replies!

 

Even though the 2004 330 wasn't on the ecm recall list,it should have been. Polaris Industries Expands Recall of ATVs Due to Fire Hazard | CPSC.gov I've replaced several on the Trail Boss 330s,but only sold a few 330 Atps and none came back in for that. This ecms function is primarily charging and fan operation.Also the oil cooler thermister works hand in hand with the ecm. Item #14 is the thermister. Dirt Cheap Yamaha & Polaris OEM Parts & Accessories – Cycle Parts Warehouse They have been know to short out not allowing fan operation,plus in most cases these engines have to get super hot before the fan even triggers on. You can check that the charging potion of the ecm is ok,charging 14 volts or more back to the battery,but as far as wiring the fan direct I wouldn't do unless you toggle it to come on when under a load or extensive low speed operation.But again if the ecm over heats,they can cause some damage. Before I started changing things or slapping on parts,this 5 buck manual can help you do a lot of testing ,troubleshooting and elimination.2004 Polaris ATP 330 Service Manual PDF Download

 

Thanks for the quick and very informative response!!! My local shop just happens to have an ECM. Thinking I'm gonna go ahead and pick it up and see if that solves it. My only concern I that it is in fact the thermistor... What would be a temp at which the fan comes on? Prior to fan operation, the oil lines were untouchable!!

 

Turn ignition key on. Disconnect the thermister connector. Red meter lead to Red/white wire,black lead to ground. Should show 12 volts coming into the harness. Jump the two thermister harness wires,the fan and hot light should come on.
Thermister- Resistance versus temperature
Fan off.. 240 degrees should show 3.5k ohms resitance on thermistor
Fan on.. 260 degrees 2.5k ohms " "
Fan on...290 degrees fan on along with hot light.
Replace thermistor if out of spec. This is from the 330 Trail Boss manual that's basically the same as the ATP. Ecms did upgrade to a new part number,but still appears to be Chinese,but the ebay box says US origin?. You can try a used one and see if it helps. Item #20.Dirt Cheap Yamaha & Polaris OEM Parts & Accessories – Cycle Parts Warehouse
http://www.ebay.com/itm/Polaris-OEM-Electronic-Control-Module-4010944-Magnum-330-Trail-Boss-ATP-2003-04-/251615354201?pt=Motors_ATV_Parts_Accessories&hash=item3a95719d59&vxp=mtr

 

Ok here's the situation now, I located both a ECM and a thermistor... ECM is $175 and the thermistor is $85. Hate to spend money I don't need to so should I start with the thermistor... The go ECM? I'm not where I can test anything right nice and really need the machine for the weekend.

 

Just my on this. The thermistor sensor is more of a nuisance than anything.A lot of air/oil cooled machines don't even use fans.Takes the 325 and 330 forever to have a fan kick on. Some have never heard their fan kick on and have owned them for years!! Same on my old Honda,it's air and oil cooled no fan,granted it goes faster than an average atv and keeps fairly cool. You can work around this if you have to have a fan that you can turn off and on if you wish or just blow it off for now. A bad thermister won't damage an engine,but the ecm could if it shorts out and gets hot enough.

 

I've decided to go ahead with the thermistor versus the ECM. Hoping that maybe it's bad and not telling the ECM to tell the fan to come on... I feel pretty sure that my machine is getting hot enough because when I've checked the oil after being this hot, it's nearly like water!! We shall see...

On another note, another reason to get the oil cooler working is because I noticed the other night the exhaust manifold was glowing red hot!! Pretty positive we had leaned it out adjusting the adjustment screw due to dirty carb...

 

Ok, unplugged the thermister and jumped across, reads hot and fan came on. So does that mean bad thermistor and good ECM? Fan doesn't seem to be running very high tho? Help! Lol

 

Fan and hot light should only come on when you jump the harness connector according to the manual. You can pull the thermister from the oil cooler,remove the o ring,check resistance on the pins when cold,then drop the sensor into a cup of boiling water. Resistance should begin to decrease rapidly. If it does the thermister should be okay. As far as the fan,again the manual shows an amperage draw test. Have only the red/white wire connected from the thermister harness connector and the thermister connector itself. You have to twist this connection(or jump the wires) to where the the orange/black wires are not connected. Have a meter set on dc amperage, touch a lead to each side of the orange/black and have someone turn the key to the on position. Fan should kick on and if it pulls more than 6.5 amps the fan needs to be replaced. Possible the fan just needs to run awhile if it hasn't hardly ever kicked on before,or could be worn bearings.. If speed doesn't increase and still runs slow,battery is good,then you can get a replacement at SPAL,the ones who make the fan for Polaris or take a chance on a used one from ebay.Think it's either a 10 or 12 inch fan,plus half the price of the oem Polaris fan.Just measure yours. http://www.summitracing.com/search/p...4%2B4294949183 My bets still on an ecm as all these modules eventually had problems and I'm a little gun shy after replacing so damn many of them! But you may get lucky with just replacing the thermister if it's needed.Again make sure the ecm is charging the battery also. Now see what this 5 buck manual link I posted can help you with.. And this is just a couple of tests it shows,and has many more,plus can help save my old fingers

 

Old Polaris Tech, I greatly appreciate all the beneficial information you've provided thus far on these issues I'm facing!! It's nice to know that there are folks out there who are willing to lend a helping hand to a total stranger! Rest assured, I'll pay it forward as soon as the opportunity arises.



I'm still at a loss at the moment as to exactly what to do... we opted not to install the thermister last night. I think I will back track and go with new ECM today based on the recall issues and your statement that all these modules eventaully ahd issues. My reason to get this fan running is because of oil temperature. The oil line leading back to the engine after going thru the radiator is untouchable it's so hot, that can't be right! Once I pick up the new ECM, I'm gonna let the current oil out and add some fresh and see how that goes.

I'll keep ya up to speed as to how this goes and in the mean time I'll be downloading the manual...

Thanks again,

KP