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Dummies guide to broken fan


Tomsmith1992
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Hi all. 

I've done lots of searching and reading up on my fan not working  on my 2003 250 beta when hot....the only problem is I don't understand most of the wording in the guides! 

Does anyone know of a source that contains images and simple explanation of finding the fault. 

'shorting the thermostat' and 'plug fan into 12v supply' seem to be the first things to try to find the fault. 

How would I go about doing the above? Where do I get access to the fan power connector? Do I just use a car battery as a power source? 

I know these are probably simple questions but it's my first ever bike!

Cheers

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Locate the coolant sensor and it’s wires, carefully ease off both connectors, now either tape both connectors together so that they make metal to metal contact or insert a paper clip or similar into the connectors to ‘bridge’ the circuit. Start engine, coolant fan should run all the time, if this is the case the sensor is not reading coolant temperature. New sensor required. If the fan doesn’t run, ensure that the fan surround or cover has not distorted or has anything wedged in it to prevent fan from spinning freely. If that’s ok, you will need a DVM that’s a digital volt meter set to 20volt, connect the meter probes to either connector and run engine, you should see a voltage reading, if no reading then you may have a break in the circuit which could be a fuse, trace the wires back to check for cuts, chaffing and eventually arriving at the fuse holder, if it’s still there. Use the DVM set to continuity to test the fuse. If the fuse is not passing current then don’t just fit a correct amp fuse, first find the reason for it to blow, such as the cooling fan motor might be seized, you will have noticed this when checking it for free turning. You may need a replacement fan motor, either way if the fan motor spins ok insert another good fuse of the correct amperage and try the system by running the engine. The fuse may have popped when something momentarily prevented the fan from operating, this could have been a twig, clump of mud or literally anything. Hope this is helpful.

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Do you mean the fan doesn't come on at all or it works but then stops working when the bike gets really hot? Assuming the former. 

FWIW - my fan stopped working and I did some basic trouble shooting (checked the thermostat and visually checked the wiring) but nothing really systematic as described above - not even aware there was a fuse in mine! The one thing that stood out was that the bottom of the regulator had a crack in it. So I just went ahead and bought a new regulator, wired it up and it was fixed. I also took the opportunity to remove excess wiring (light circuit etc.), moved the kill switch earth and ended up leaving the fan hard wired on (laziness).  

It can be daunting but the wiring is so simple on these old bikes that it's worth having a go and trying to figure it out 

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Just tried joining the two connectors at bottom of radiator together with a piece of wire, once started the fan started spinning straight away so thanks for that advice very helpful! 

Just gotta look for a new thermostat now....but will use this temporary fix so I can ride this weekend. 

Thank you for help it's much appreciated! 

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17 hours ago, Tomsmith1992 said:

Just tried joining the two connectors at bottom of radiator together with a piece of wire, once started the fan started spinning straight away so thanks for that advice very helpful! 

Just gotta look for a new thermostat now....but will use this temporary fix so I can ride this weekend. 

Thank you for help it's much appreciated! 

Pleasure to help you, glad it was straight forward for you, enjoy your ride??

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