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 Post subject: WR250R cooling fan electrical problem -HELP
PostPosted: Fri Jan 15, 2016 8:18 pm 
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80 cc

Joined: Sun Jul 12, 2015 2:42 am
Posts: 34
Hi all, I am a new member to the site, had a WR250R now for nearly a year and really enjoying it. I have carried out a few mods so that it fits me better, mainly lowering and seat scalped a bit, the only thing I would moan about is its weight when I have dropped it a few times on trails. Really glad I have joined the TRF and enjoy the forums.
I need some help with an electrical problem with the cooling fan, not long ago it wouldn’t come on and the engine was boiling so I eventually diagnosed the problem to a corroded terminal in the relay, I cleaned it and put loads of Vaseline around it, ran a check on the ECU 51 (fan relay) and it activated 5 times as it should – great I thought.
Next time out riding, every time the fan comes on so does the ENGINE WARNING LIGHT, fan goes off, amber warning light off. Another problem it didn’t have before is that when the engine is off/ignition on, the fan wont run, as soon as engine started again, fan runs along with the warning light.
I have cleaned the GREEN overheat sensor, played with the ECM but no difference, anyone gotta an idea??


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 Post subject: Re: WR250R cooling fan electrical problem -HELP
PostPosted: Sat Jan 16, 2016 12:29 pm 
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650 cc Monster
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Joined: Fri Dec 07, 2012 2:22 pm
Posts: 2439
Location: Romiley
Greetings,

I do not have experience of this model so I can not provide you with a 'silver bullet' to cure the problem. However I have tracked down a possible wiring diagram which I attach and hope might help you.

Let's look to basics first. Instead of vaseline on the terminals try plumbers silicon, more expensive but can provide superior results. Disconnect all of your connections, thoroughly clean them with brake/clutch/carb aerosol spray, pop some silicon grease in the holders and reconnect. Check that both battery terminals are making a good electrical connection and are secure. Fully recharge and test the battery.

Since you have an operational fan, i.e. the motor operates, then I would suspect that the temperature sensor would be the next and cheapest item to test. Try to suspend the sensor in a container of water, attach an ohmmeter to the terminal and body making sure that they can not get wet and short! Gently heat the water up and watch the meter reading for changes, alternatively try a new unit.

After that it looks like you might need the assistance of a Yamaha mechanic/electrician to test the 'black boxes' especially number 29 rather than the ECU or ask some one who has specific knowledge and experience of the model. Owen at Manchester Extreme might be able to answer your question, call 01614835559

Perhaps my answer might bump your question up and attract somebody else to come along with more knowledge.

Sorry that's all I can think of at present but let us know what you eventually find.

TTFN

Hugh.

Attachment:
WR250RX Wiring Diagram.jpg
WR250RX Wiring Diagram.jpg [ 369.78 KiB | Viewed 10111 times ]

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 Post subject: Re: WR250R cooling fan electrical problem -HELP
PostPosted: Sat Jan 16, 2016 12:48 pm 
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650 cc Monster

Joined: Fri Jan 07, 2011 9:11 am
Posts: 2440
Location: St Albans
Mitso wrote:
Hi all, I am a new member to the site, had a WR250R now for nearly a year and really enjoying it. I have carried out a few mods so that it fits me better, mainly lowering and seat scalped a bit, the only thing I would moan about is its weight when I have dropped it a few times on trails. Really glad I have joined the TRF and enjoy the forums.
I need some help with an electrical problem with the cooling fan, not long ago it wouldn’t come on and the engine was boiling so I eventually diagnosed the problem to a corroded terminal in the relay, I cleaned it and put loads of Vaseline around it, ran a check on the ECU 51 (fan relay) and it activated 5 times as it should – great I thought.
Next time out riding, every time the fan comes on so does the ENGINE WARNING LIGHT, fan goes off, amber warning light off. Another problem it didn’t have before is that when the engine is off/ignition on, the fan wont run, as soon as engine started again, fan runs along with the warning light.
I have cleaned the GREEN overheat sensor, played with the ECM but no difference, anyone gotta an idea??



Check all of your Earths.

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 Post subject: Re: WR250R cooling fan electrical problem -HELP
PostPosted: Sat Jan 16, 2016 3:25 pm 
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80 cc

Joined: Sun Jul 12, 2015 2:42 am
Posts: 34
Thanks for that Hugh, I didn't mention that it has thrown up error code 21 - Coolant temperature sensor error - after the fan has activated with the Engine warning light. Last time however, it showed there was 1 error code but wouldn't display the error.

I was wondering if because the bike boiled for a bit it may have damaged the temperature sensor, although the fan appears to come on/off as expected albeit with the amber warning light.

I am going to try the electrics again first and clean the relay out as suggested, check all the contacts and try dielectric grease iso Vaseline. The guy in Manchester may provide a useful source.

Anybody know where the temperature sensor is? Its not the green socket at the rear of the engine is it?


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 Post subject: Re: WR250R cooling fan electrical problem -HELP
PostPosted: Sat Jan 16, 2016 5:56 pm 
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650 cc Monster
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Joined: Fri Dec 07, 2012 2:22 pm
Posts: 2439
Location: Romiley
Greetings,

I think that it is located at the rear of the engine, to the right of the thermostat, just below the inlet manifold.

It normally has a copper washer for sealing and two terminals inside of a plastic block.

You could always test the sensor, which is a thermistor, in situ and watch the resistance reading alter as the engine warms up. The output varies with temperature, as the temperature increases the resistance decreases, so when cold the resistance might be 4500 - 6500 ohms as the temperature increases you might get a reading of 250 - 400 ohms. I have known folk use a light bulb in series so dull when cold brighter as the engine heats up.

I think that the feed voltage to the unit is constant at about 5v even though the battery is a nominal 12v system. You would need a Yamaha workshop manual for exact readings.

Hope this helps.

TTFN

Hugh.

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 Post subject: Re: WR250R cooling fan electrical problem -HELP
PostPosted: Thu Jan 21, 2016 8:53 pm 
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80 cc

Joined: Sun Jul 12, 2015 2:42 am
Posts: 34
PROBLEM – FAN TURNS ON WHEN ENGINE IS WARM (as normal) BUT THE ECU AMBER LIGHT COMES ON AT THE SAME TIME AND WHEN THE ENGINE IS CUT THE FAN STOPS EVEN WITH IGNITION ON.
Today I managed to spend some time working on the bike –

• Battery terminals good
• Cleaned the relay and used dielectric grease
• Battery is reading 12.5v
• Temp sensor – I think that has to be working as the fan comes on along with the ECU light when the engine warms up so I haven’t made a separate test on it.
• The earths seem fine
• Swapped the headlight relay for the fan relay and vice versa – both relays work ok in lights and both throw up same ECU light on with fan.
• Disconnected the battery and held + and – together to discharge the capacitors (cold reset)-THIS THEN BROUGHT UP ERROR CODE 21 iso OF 0, but after subsequent running of fan it displays a 0 error code
• 21---Coolant temperature sensor, open or short circuit detected. • Open or short circuit in wire harness. Defective coolant temperature sensor. Fault detected in ECU

Any more ideas gratefully accepted.


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 Post subject: Re: WR250R cooling fan electrical problem -HELP
PostPosted: Fri Jan 22, 2016 1:07 pm 
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650 cc Monster
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Joined: Fri Dec 07, 2012 2:22 pm
Posts: 2439
Location: Romiley
Greetings,

The more I think on this one the more I think the problem mighty simply be;

the coolant temperature sender unit which could be passing an incorrect signal to the ecu, in that it might be switching the fan on but at the wrong temperature expected by the 'brain', e.g. too hot or too cool for the expected parameters

alternatively, perhaps the diode in the radiator fan relay is allowing a back emf to signal the ecu as to a problem with the fan even though the fan motor is operational

So off you go back into the recesses of that place which is cold, dark and full of foul words to take on the Gods of 'electrickery' :lol:

TTFN

Hugh.

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 Post subject: Re: WR250R cooling fan electrical problem -HELP
PostPosted: Fri Jan 22, 2016 11:08 pm 
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50 cc
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Joined: Sun Mar 29, 2015 8:04 pm
Posts: 4
Location: Cumbria
Study the diagram if this relates to your bike year, the answer is within this to allow you to find the issue you describe. check the voltages where 12 volts should be on this cooling cct both off and on, provide clean/new earths and diss existing paths to eliminate internal loom wiring, remember to confirm earths with a load(i.e. a bulb tester), so the wires can carry load and finally try to measure the millli/mirco amps going through your temp sensor...because this is what the ecu will be looking at to allow the the fan cct to play. ;)


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 Post subject: Re: WR250R cooling fan electrical problem -HELP
PostPosted: Thu Jan 28, 2016 10:00 pm 
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80 cc

Joined: Sun Jul 12, 2015 2:42 am
Posts: 34
There is a sensor at the rear of the engine with a green plug, when I short it out it brings on the overheat light, is this also the temp sensor??


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 Post subject: Re: WR250R cooling fan electrical problem -HELP
PostPosted: Thu Jan 28, 2016 10:03 pm 
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650 cc Monster
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Joined: Fri Dec 07, 2012 2:22 pm
Posts: 2439
Location: Romiley
Greetings,

I think it is but could you photo it and paste the picture on here :?:

TTFN

Hugh.

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