Hi, I have a 2007 polaris trail boss 330 and the oil temp light comes on when the key is on, regardless if it is running or not. It takes about 15 seconds after the key is turned on to come on. What should i look for Thanks

 

It can be the thermistor sensor on the oil cooler that shorts out causing the constant light. Or in the case of older models,could be either the sensor or thermistor control module which your machine doesn't have. It's replaced by an ecm module that incorporates the thermistor module along with charging,fan operation,etc. This module wasn't on the ecm recall,but should have been imo. Either part is fairly expensive and sensor is starting to show NLA at a lot of places. Here's the readings I posted several years back on what resistance the sensor shows. "(Part #4010934.) BUT according to the manual I have though, at 77 degrees, resistance on thermistor should be 100 k ohms + or - 15% (fan should be off) At 260 degrees + or - 15% the thermistor resistance should be 2.5 k ohms (fan turns on). If this is within range on the thermistor,then the control module(ecm) could be faulty as it controls the fan(from input from the thermistor) and also controls charging back to the battery.Then manual says to replace the ecm module.You can take a heat gun if you have one or boiling water to check out the thermistor resistance as close as you can get." If the thermistor checks out,then it's probably a bad ecm. Around 200 bucks.Item #18 is the ecm. Dirt Cheap Yamaha, Polaris, Suzuki & Kawasaki OEM Parts & Accessories – Cycle Parts Warehouse
Item #12 is the thermistor sensor.Dirt Cheap Yamaha, Polaris, Suzuki & Kawasaki OEM Parts & Accessories – Cycle Parts Warehouse

 

I just replaced the ecm because the fan was running all the time, even with the key off. I took the ecm apart and it was visibly burnt. Every thing works fine now excet that the light is on all the time, the fan does not come on. The light is on even if the bike is not running, with just the key on. It is a 2007

 

You might try to unplug the ecm to see if it can reset. If it doesn't I'd check out the thermistor sensor resistance reading. Could be shorting out,going through the em and just triggering the light.

 

I will try to unplug the ecm, Should i do it with the key on? Also, How would you go about checking the "thermistor sensor resistance reading. Could be shorting out,going through the em and just triggering the light." Im not real smart on this stuff. Also do you think it will hurt to ride it with the light on?

 

Key off on the ecm.. Just unscrew the sensor from the oil cooler. Check the resistance on the two leads at room temperature. Place it in a cup of boiling water,resistance should drop. Before you take it out you can check it while it's still installed. If it zeros out on the meter,it's shorted out. If the thermistor is in range,could be a faulty NEW ecm module. Had a few of those also during all the recalls when I was replacing the Chinese modules with the US made modules..

 

I dont have any thing to test it with. I might try to find a thermistor somewhere and just try a new one. Where would be the best place to find one. By the way, thank you for all your help.

 

Just get a cheap meter at any auto store,harbor freight,etc. Place settings on ohms and check out the leads. If the thermistor is bad,possibly you can match it up at an auto supply and just use your connector end. At least worth a shot rather than pay this high a price for one.$88 if you can find one. Plus one last alternative..IMO they just needed the oil cooler and didn't need the fan as most don't kick on until the temp hits 260 degrees.Many owners haven't ever heard their fans kick on. As long as the ecm is charging the battery properly,you could just disable the light by just snipping one indicator wire. Just a thought on this..

 

Thank you so much for all the help. I will go get a cheap tester just for peace of mind. Now for the stupid question, You say test the leads, what are the leads? The wires going to the thermistor or the thermistor its self. I told you i was dumb . Thanks again for all the help. You seem to know what you are talking about. I sure appreciate it.

 

Brown wire(ground wire) that leads to the indicator bulb. You can just snip it and the light will go off. If you find a solution whether it's the thermistor sensor has shorted out or a problem with the new ecm,you can always hook it back up if you wish.