I have a shop manual for this machine and It doesn't give the info I am looking for. From what I understand the temp light could be turned on w/ the oil temp sensor and/or the coolant temp sensor. After running the engine 10 mins. my temp light is coming on but the fan isn't coming on. I hot wired the fan and it is fine. I also checked connections for corrosion etc. and they seem fine. coolant level is good in the radiator and reservoir. Oil level is good. I know the ECM takes all the info and altimately controls the functions. Does anyone know if the coolant temp sensor is the primary/ only sensor that sends the signal to turn on the fan?
I am wondering how My temp light is no but my fan is not getting the power to turn on. The only explanation I can come up w/ is that the Oil temp sensor is turning on the temp light and the coolant temp sensor is not working at all.

I plan to replace the coolant temp sensor ( and thermostat, while the coolant level is down ) to see if that fixes it.

Any other Ideas/ comments ??

Thanks

 

No offense intended, but you checked the cooling fan fuse?

Since you have the manual, look in the Lights, Meters, Switches section. It describes the location of the oil and the coolant temp sensor locations, and how to test them.

 

I checked the fuses first...... Sometimes the obvious is overlooked.....

Yeh... I found all the sensors. Haven't check them yet. I was hoping someone had been thru this already. Common sence tells me it is the coolant temp sensor or I have a faulty ECM.

I'll get back to it this weekend.

Thanks for the reply !

 

Good luck with it. You might also go over to rinconriders.

 

Once the unit is warm, or the temp light is on. unplug the wire on the sender below the carb on the cylinder and ground it out. If the fan runs and the light goes out after the fans runs for a short time, replace the sensor.

----- Gimpster -----

 

OK ... so .... you are saying when the sensor is working it completes the "ground side of the circuit.
I will try that.

Thanks for the reply.

 

Gimpster,
I replaced the coolant temp sensor and the Thermostat, $60 later..... No change!
( I ordered the parts before I posted here ) I thought for sure it was the coolant temp sensor.

I tried grounding the wire off the Coolant temp sensor. The fan ran for a long time and the light never went off. Does that mean it is the oil temp sensor turning the light on?

I'm thinking the coolant isn't hot enough to turn on the fan and the oil temp sensor is giving a false reading. To check the oil temp sensor can I pull the wire off the oil temp sensor and see if the light turns off ? Or I can check the sensor ohm readings while installed in the motor to see if they are way off base from the shop manual parameters.

What ohm readings should I get on the sensors when the engine is cold ?? The shop manual gives you ohm readings for 77 deg F and 302 deg F for the oil temp sensor. The high today is supposed 36 deg F here in Ohio.

I am tempted to get an auxillary temp sensor to mount somewhere for future reference. I could at least verify if it is really overheating or if the electronics are giving me a false reading.

I might have to buy a thermometer for temps up to 300 deg F to test these sensors before I am done.

Thanks for the help !

 

My book says that if the temp light stays on after the fan shuts off, try unhooking the coolant sensor and see if it kills the light, and if that doesn't do it unhook the oil temp sensor. If that kills the light, check the oil sensor. If not, check for a short between the sensor and the PCM.

It also says 1.21 to 1.32 k at 103f, but this is from a manual for 680 Rincon, so it might be different... I see where it lists values for 77 and 302 for the 650...

 

Jeffin TD,

It sounds like the new book might be a little more informative ... my book ( 2003 shop manual ) has no information on what to look for if your fan will not come on. I know a little common sence goes a long way here. It would be nice if it addressed this more directly. I checked the obvious...... fuses, hot wire the fan to see if it runs, broken wires....

I sart the motor let it warm up enough to turn off the choke and ride for 5- 10 mins or so before the temp light comes on... Long enough to make me wonder if it Really is Hot.... A simple temp gage would be Great at this point !
When I see a RED temp light and I think ...Oh Crap the engine is HOT ..... hum ....and cripe .... it is Hot because the fan is not running at all .... not necessarily true ! UP till now I have been thinking it Really IS HOT ! Better to error on the safe side I guess.

My fan will not turn on at all. I have to short the coolant temp sensor wire to get the fan to run. ( Like Gimpster suggest above )
After letting the fan run the light will still not go out. ( NOW ... I don't think it is Really Hot enough to turn on the fan)


What sensor actually signals the ECM to turn on the fan ???? I would assume the Coolant sensor does...??? It could be a combination of sensors doing it... ???

I have checked for continuity on all wires on the coolant temp and fan circuits. from ECM to both. I have been stuck on the coolant temp sensor and fan circuits and haven't looked into the oil temp sensor yet. Tunnel Vision... My mistake ....

AS you suggested.....
I have tried to unhook the coolant sensor and the light is still on. I haven't tried unhooking the Oil temp sensor yet. I will try that. I will also check for continuity on the wiring from the ECM to the oil temp sensor.

I have my Rincon scattered all over the garage to get to the ECM and fan plug.

At this point I'm not putting it back together till I get it fixed.... It will take me 2 hrs to put all the plastic back on ! .... hahaha ... You gotta laugh to keep from getting Pissed off !

I should have some time to work on it tonight. I will post my results.

Thanks for the help !

Just curious Jeffin TD .. Pro Rider in what kind of racing ??

 

OK, so only after the thing runs for a while the temp light comes on, but the fan does not...

The fact that the light is off initially to me would rule out a short in the harness.

You say you checked the fuse, and that you hot wired the fan and it runs, and that it also runs when you ground the coolant sensor wire.

I'm wondering if that leaves the oil temp sensor. I can't imagine the oil temp got hot from running a few minutes in N with no load on the thing...

Anyhow, the Pro Rider thing isn't anything I put up. I think it's a little moniker the web page uses to incidate how long someone's been here or how many posts they have or something.