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Hi.

I just got my first quad, a honda trx300. 1999. I bought a haynes manual for it and it has helped with almost everything i have needed.... however the wiring diagram is for the pre-98 models.... and does not even mention the cooling fan. (even tho the manual says its up to 2000 model on the cover)

There are 2 wires under the front plastics, under the instrument panel, hanging loose... 1 of them powers on with the ignition and the other is an earth. I have not had the fan come on yet and was wondering what was wrong, I traced 1 of the wires of it to the CDI/ICM unit, Does the fan come on itself when it overheats? or does it need to be wired to a switch and that is why I have loose wires? The wires are 2 male push on type connectors.

I did not want to cut the wire to the CDI to power the fan, because im sure it goes there for a reason.

Any help would be appreciated before I butcher it and wreck the quad before it gets a chance to wreck me.
 

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Um those quads were air cooled back then the fan must have been an addition. What color are the wires?
 

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Yeah, like TRX2fiveO said, the TRX300 utility didn't come out with a fan. I have seen a place under the fenders in front of the motor that looked like a shroud where a fan would bolt up, so maybe it was an option or something, but I've never seen one on one. I have owned a lot of TRX300's and I never needed a fan. If you think you need a fan, I would just wire it up through a toggle switch and turn it on when needed. I don't know why a power wire would be running from the CDI box, but I don't think I would run the fan off of a wire coming from the CDI box. It could damage the CDI. I would run a power wire straight from the positive battery terminal, with an inline fuse.
 

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^^^^^agreed
 

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u have to run wires to a swich it dosnt have a sencer like the other bikes so wire it to a swich and u will be fine
 

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On external oil cooler woould do more justice than a fan on an air cooled engine. the fan isn't going to help you at all if very little. the oil cooler will howerev help shave about 5 to 7 degrees off.
 

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you have to wire them to run full time, they do not kick on and off. those wires could be for you fan or a break light.
 

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more than likely..the wire that is comming off the cdi..is probally a lead to a oil temp sensor control unit..the trx350d has a ex oil cooler with fan..and it all ties into the oil temp sensor..i'm pretty sure they never came out with the ex oil cooler on the older trx300's..it musta been an option back then..but..like everyone else here has said..most trx300's never came with them..but..if your bike had a ex oil cooler and fan installed..yes..that power lead from the cdi would tie into a oil control box..the way it works is..your oil temp sensor see's the oil is hot..sends the signal to the oil/fan control unit..if this detects an over heat..it turns the fan on...now..as far as my year and make for my bike..it's set up like that..only thing that my oil control unit will do extra < not sure about the trx300 model >..is if my oil gets to hot..and the fan is broken soo to speak..is the oil control/fan unit will tell the main cdi unit to shut the bike down...too keep it from seizing up..that was honda's theroy anyway..i haven't had my bike back together..and road it yet to make sure the fan part works..i hope it does !..lol
 

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Since we're talking about Fans here I was wanting to add a fan to my 300 and just put it on a relay and a switch. I have a small fan off of a car its almost perfect size to mount in the front where the little ears are for the Optional fan. My question is will that fan draw too much? should I find something a little less powerfull? Mostly it would be used when spraying or pulling my pull behind mower.
 

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See if the fan has a power rating printed on it somewhere. To make the math easier, figure 1 amp per each 10 watts and I wouldn't use anything over 5 amps, though you could probably get away with much more. I doubt the fan will pull 50 watts, so you should be fine.
 

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I'll check to see if there are any markings on it, I'm pretty sure it was the helper fan for AC condenser on a lil mazda or something. Its a tiny lil thing.
 

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if it will work fourtrax..make sure to put a inline fuse for it..otherwise..your going to be blowing alot of fuses
 
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