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Discussion Starter #1
So I was out today doing some grouse hunting, went up a few trails (maybe 45 mins of non stop slow driving) and hills. I got to the end of a trial and when I went to turn around I noticed the ENGINE HOT was flashing, I shut the machine off and coolant started pissing from the overflow bottle.

I turned the key on and the fan fired up for about a second and then quit, tried starting it up and the fan went for another second and quit again, it would not turn again again no matter what I tried.

Checked all the Fuses and they are all good and in tight.
I ran 12v directly to the fan leads when I got home and the fan is not the issue. In fact, I bypassed the connector and hooked up a toggle switch so that I can go riding tomorrow without worrying about overheating again.

I would rather not keep the toggle forever, but it will do until I can figure out why the fan is not coming on by itself.

I would assume it would be the temp sending unit aside from the fact that it worked to send the ENGINE HOT signal to the speedo. Possibly not the same part that sends signal to the fan to turn on?

Any help is appreciated on the matter.

Thanks
 

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Sorry you are having problems. These are usually pretty solid machines.

I do believe the fan sensor is separate from the hot light sensor.

Take a look at the diagram below. #4 and #13 I would assume the radiator sensor is running the fan, and the engine sensor is what is tripping the hot light, and shutting down the motor if necessary.

I'm not sure how to test either, but I'm sure a multimeter and knowing what is the normal range and testing procedure out of a service manual if you can get one would have the step by steps how to.



1 4012192 Rectifier/Regulator 1 USAGE
2 7512084 Screw 2 USAGE
3 4010298 Sensor, Hall Effect 1 USAGE
4 3085352 Sensor, Thermo [Engine Thermal] 1 USAGE
5 5433733 Nut, Ignition Switch 1 USAGE
6 4110164 Switch [Brake Pressure] 1 USAGE
7 5433534 Cover, Key 1 USAGE
8 4010278 Blank, Key, Series 2000, 2100, 6700, 6800 NOTE: Your key can be duplicated only by obtaining a key blank from Polaris and having it cut by mating it with your existing key. 1 USAGE
8 4012165 Switch, Key, 3 Position [Incl. 5,7, and Key] 1 USAGE
8 4010321 Blank, Key, Series 2200, 2300, 2700, 2800 NOTE: Your key can be duplicated only by obtaining a key blank from Polaris and having it cut by mating it with your existing key. 1 USAGE
8 4010278 Blank, Key, Series 2000, 2100, 6700, 6800 NOTE: Your key can be duplicated only by obtaining a key blank from Polaris and having it cut by mating it with your existing key. 1 USAGE
8 4012165 Switch, Key, 3 Position [Incl. 5,7, and Key] 1 USAGE
8 4010321 Blank, Key, Series 2200, 2300, 2700, 2800 NOTE: Your key can be duplicated only by obtaining a key blank from Polaris and having it cut by mating it with your existing key. 1 USAGE
9 7517658 Screw 1 USAGE
10 5132382 Cap 1 USAGE
11 3233835 Switch [Gear Position] 1 USAGE
12 3233834 Ring, Retaining 1 USAGE
13 4010808 Sensor, Thermal Harness [Radiator]
 

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Discussion Starter #3 (Edited)
Thanks, I will see if I can find operating specs for those and check it out with my multimeter.

Gets frustrating when a new problem arises every 2nd time out.

Assuming here that #4 is the ENGINE HOT signal and #13 is the sending unit for the fan to turn on at X Temperature, oddly enough I did a continuity test on both sides of the plug earlier today on #13 (I suspected sensor side would come up with nothing as it had cooled down and would use a thermal switch to trigger the fan and only make contact after a certain temperature) but I would have expected the engine side to get a signal and it didn't.

Only spec I can find looks to be the engine sensor and not the rad sensor:
 

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There is also a fan relay that might be the problem if the thermo switches check out. Also check all connections & make sure they are clean & not corroded.
 

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Not sure if the 09 is the same as the 08 500ho, but they are supposed to fail to a fan on.

The sensor on the clutch side of the engine by my overflow is what triggers the fan to kick in. If it is unplugged while running, the fan will turn on and it will flash a wrench on the display. I would check the relay connections to ensure there's no corrosion.
 

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Discussion Starter #6
I will check relay and relay connections tomorrow.

The relay (or its connections) sounds about right. If the switch doesn't come on the fan won't go.

Thanks for the diagnosis. This is why I love public forums......helpful ppl. :-D
 

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Discussion Starter #7
Tested the relay itself yesterday and the relay is working, there is no resistance between the leads coming from the relay area to the temp sending unit connector. I am assuming the problem lies somewhere in the rats nest of wires Polaris has in there so I will have to pull all the plastic off....again.....and test everything under there.

Is there a way to pull the relay and manually jump the connection to see if it fires up the fan? I'm not to electrically inclined when it comes to relays, it took 4 youtube videos yesterday just to get relay tested. LOL

I certainly know why they call it a wire "cluster".
 

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Start the machine and pull the connector off the temp sensor. It should default to running the fan.
 

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Discussion Starter #9
Neither of the machines I have defaulted to fan on. The 500 or my wife's 400. Her machine did though have resistance on the lead from temp sensor to relay when I probed it.
 

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Ok, must have changed it in 09. You can jump the fan at the relay block. Pull it out and two of the terminals can just be jumped w a piece of wire. It'll be the two that go through the switch not the ones that operate the coil. Should be 87 and 30.
 

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Discussion Starter #11
Ok, must have changed it in 09. You can jump the fan at the relay block. Pull it out and two of the terminals can just be jumped w a piece of wire. It'll be the two that go through the switch not the ones that operate the coil. Should be 87 and 30.
Excellent thanks. At least if that makes the fan go then I can narrow it down to the wiring on the other side of the relay.
 

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Discussion Starter #12 (Edited)
OK so I have continuity from the Rad Sensor lead to the relay. (Red/Black wire)
Also have continuity from the Orange/Black wire which goes from the Temp sensor to the fan.

Question I have is should the relay be always on or always off? When I key the machine on the relay clicks, would this not send power through to the fan?

Pole 85 in the relay socket has 12v when the key is on (Red/White Wire)
Pole 87 is the Red/Black wire mentioned above from the Rad Temp Sensor
Pole 86 is Ground? (Brown Wire)
Pole 30 is a Red wire I cannot trace.

If everything was working the way it should if the temp sensor connector was jumped it should trip the relay and therefore power up the fan?

Jumping 30 and 87 in the socket does nothing, jumping the sensor connector does nothing (does not trip relay).

Sorry for all the questions but I am not an electronics type of guy.

EDIT: Engine Sensor failure should default fan to on...... just found this:
Coolant passes through the cylinder and by the sensor probe,
varying a resistance reading which is relayed to the ECU. This
signal is processed by the ECU and compared to it's
programming for determining the fuel and ignition
requirements during operation. The ECU also uses this signal to
determine when to activate the fan during operation. If for any
reason the engine temperature sensor circuit is interrupted the
fan will default to “ON
Picture shows the sensor in the side of the engine, not into the radiator.

Disconnecting this Sensor did not initiate the fan either. :(

Bad ECU perhaps now?
 

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Either 86 or 85 should be grounded, the other should be energized from the ecm when is sees the current adjust on the wires to and from the temp sensor. As it heats up the resistance changes( not sure if this particular system raises w temp rise or lowers). Once the propper current flow is reached it should send 12v to the relay's coil ( 85/86).

30 should be energized by the ignition, and 87 should go to the fan. So when the ecm sends the signal of 12v to the coil portion of the relay, it closes the contact portion.
 

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Discussion Starter #14 (Edited)
Well with no relay in, ignition on and just probing the socket with multimeter I get the following:
85 - 12v
86 - 0v
87 - 0v
30 - 0v

So it seems to me that the ECU is sending power to the relay constantly (defaulting fan to on) but 30 is not energized to send voltage to 87 which runs to the fan.

Does this sound correct? If so I will have to trace the red wire going to 30 to see why its not powered.

Thanks also for your patience. :D
 

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30 should have power at all times, you have to trace 30 to a fuse
This sounds correct, its not from the ignition but is fused.
 

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Discussion Starter #17
OK. I traced the wire back and this guy seems to be the problem.


Hopefully I can pick one up at Canadian Tire or Lordco.
 

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Hey sorry for the high jack but I have a slightly related question about my 800. Do the value line machines go into limp mode like the xp's? Thanx in advance and for the valuable information about the cooling system electrical system.
 

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Discussion Starter #19
Woo hoo..... Replaced the fuse pictured earlier, ran the bike for about 20 mind on idle and the fan just fired up.

Thanks for all the help with the relays and such. It lead to tracing the bad fuse. :D
 

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Alright, feels great to get an issue solved! Always check fuses. They can and will make your life hell if they are unknowingly blown. Trouble shooting can be a pita.
 
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