Jump to content
Sign in to follow this  

i need help wiring a computer fan

Recommended Posts

i thought this was going to be easy, but i guess i'm a bigger electrical idiot than i suspected.

spent a good amount of time with no success, so i figured i'd ask here.

 

trying to wire a computer fan direct to battery with an in-line fuse and toggle switch to turn fan on & off.

 

the fan has 2 wires coming off motor (red & red w/black)

the switch has 3 terminals (pos/light/neg)

 

everything i've tried has the fan running constantly(cannot switch it off)

the switch illuminates when i turn it on.

 

can anyone tell me what wires need to go where

 

thanks

Share this post


Link to post
Share on other sites

Switches don't have positive and negative, they have an input and output. Are you trying to wire both the positive and negative wires to the switch?

Share this post


Link to post
Share on other sites

Use the switch to "interrupt" one leg of the wires. Either positive or negative. Wire one lead to one post on the switch then continue that on to your fan from the other post. Provided it is a single pole switch.

Share this post


Link to post
Share on other sites

Put in other words:

 

Connect RED W/BLACK wire from the fan to ground.

Connect RED wire from the fan to POS terminal on the switch.

Connect NEG terminal from switch to one terminal of the inline fuse.

Connect remaining terminal from inline fuse to Battery (+) post.

 

If the fan spins backward from desired rotation, reverse wires from first two steps.

Share this post


Link to post
Share on other sites

Sounds like you bypassed the temperature switch wire coming from the radiator. Computer fans are always on, so the controller will be the temp sensor that is in the bung at the top of your radiator if its an S, and if you have an E i believe you dont have one, and would have to buy afyer market. Can you give some more background as to why your using a computer fan, and details about which bike you have? I succesfully wired a computer fan to mine after cutting a dear in half, and would love to help you get your fan going.

As a side note, what is the cfm rating of the fan and where did you get it?

Share this post


Link to post
Share on other sites

Switches don't have positive and negative, they have an input and output. Are you trying to wire both the positive and negative wires to the switch?

yes, i was... and yes, i am an electrical idiot as mentioned - thanks

 

Use the switch to "interrupt" one leg of the wires. Either positive or negative. Wire one lead to one post on the switch then continue that on to your fan from the other post. Provided it is a single pole switch.

 

this helps - thanks

Put in other words:

 

Connect RED W/BLACK wire from the fan to ground.

Connect RED wire from the fan to POS terminal on the switch.

Connect NEG terminal from switch to one terminal of the inline fuse.

Connect remaining terminal from inline fuse to Battery (+) post.

 

If the fan spins backward from desired rotation, reverse wires from first two steps.

 

love it - put it into idiot terminology for me - thanks. will try this tonight.

Sounds like you bypassed the temperature switch wire coming from the radiator. Computer fans are always on, so the controller will be the temp sensor that is in the bung at the top of your radiator if its an S, and if you have an E i believe you dont have one, and would have to buy afyer market. Can you give some more background as to why your using a computer fan, and details about which bike you have? I succesfully wired a computer fan to mine after cutting a dear in half, and would love to help you get your fan going.

As a side note, what is the cfm rating of the fan and where did you get it?

gonna use this on S model with ims 2.6 tank - i no longer have the oe fan, which wouldn't fit with the ims anyway as far as i remember. not using the oem fan wiring, so no sensor. i just want to wire it direct to the battery with a switch that lets me turn it on & off. fan is from radio shack - don't have specs with me now.

 

i am running a hare scramble sunday. last time i ran this race the bike over-heated early on in a slow moving section & i pretty much ran the whole race with over-temp light on & cooked the motor. was able to finish, but....

 

sooo,,, i just need this to last me one 5 mile race. will most likely leave it on the entire race.

 

thanks again to you all for your help - will let you know how it works out.

Share this post


Link to post
Share on other sites

that temp light only comes on when your 5 degrees away from critical. just an fyi. the sensor opens up much sooner, that's why i suggest wiring to the sensor. its easy. doesn't matter what wire you pick on the temp sens plug, wire your black wire to one, and the other goes back in to the harness at ground i believe. just like a switch would.

 

Since your going to be constantly running it hard, let me impart some awesome knowledge about computer fans: they hate blockage.

They hate any obstruction. In my experience, my single high output cpu fan cannot cool my bike while at idle at a stand still. I have to shut it off. Granted, the fan extends my sitting time substantially over no fan, but i have learned from building custom computers: push-pull is where it is at.

On liquid cooled computers, their radiators almost always have a fan on BOTH sides of the radiator. This allows one fan to drive the air in, and the second pulls it out, making the work of the fans much easier, and anywhere from 3 to 4 times more efficient. Cpu fans push air, but not very far.

If your unsure about your cfm rating, then you probably did not buy a super high tech one. Buying from radio shack further confirms this. I HIGHLY RECOMMEND buying a second one and just connect it right into your current setup (ie both fan positives and negatives run to the same point). This give you close if not better than stock cooling. I wish i had done so to mine when i installed a single fan. Trust me, its worth it. Also, if a stick breaks the fan in front or a rock, the second will keep going. Don't worry about water hitting them, despite the fans being designed for computers, they work submerged. I ran on submerged in a 5 gal bucket to prove to my father the cpu fan works as a replacement. It was like a boat motor lol

 

 

**note: the temp sensor is not apart of the fan wiring. its its own little thing. look at the top of the radiator (side with fan, the other side has one as well which is your warning light indicator sensor), there are two wires coming out and heading up to the harness to a plug. THIS is the temp sending unit that turns the fan on. if it were not there, you'd have an open hole in your radiator. unless you removed this earlier and plugged it. just use the above wiring instructions, but instead you could use this sending unit in palce of the switch since it is a switch that automatically turns on at a pre-determined temp, which i believe is around 200 degrees. the temp light comes on around 240 degrees, like i said near critical. this sending unit does NOT have to go through the bike's harness, Suzuki just did that to tidy up their wires. cut the plug off the end and use the two wires like you would a switch. it works both directions, the wires are not specific. its just open and close circuit.

 

Also, though the temp light comes ON at 240 degrees, it will NOT TURN OFF till it gets below 210~ degrees. So don't panic if it sticks on. once its off, you know its cooled way down. this was done by Suzuki i think to encourage you to stop after it comes on, since it wont turn off at the same point it turns on.

 

i researched all this in the Clymer manual and other sources after my deer accident, i spent a long two days fevering over a replacement fan and found all these tidbits out.

Edited by Ivan-the-hunter

Share this post


Link to post
Share on other sites

Hi,  Been a while since we talked.  Yes, a switch is wired in series with power to an accessory.  And in this case you have 3 terminals on the switch for a lighted switch. I take it your switch is marked POS, LIGHT and NEG.  Connect POS to the battery, NEG to the red wire to the fan and LIGHT to a wire going to ground.  The third wire in this case marked LIGHT is ground for the internal light in the switch.  There are various kinds of lighted switches. Some are lit all the time some the light comes on only when the switch is ON.  You will just have to experiment with how your switch works.  If you do not care about the light, omit the wire from the LIGHT terminal.

 

Frankly I'm guessing here so if you do not get the desired result, reverse the fan and light wires. (POS to battery NEG to ground and LIGHT to the red wire to the fan) I suppose this might make more sense if the switch was intended to turn on an accessory light.

 

And of course connect the other fan wire to ground.  It is possible (I'm not sure) if you reverse the fan wire connections, the fan may run in the reverse direction.

Share this post


Link to post
Share on other sites

between you guys & a diagram i found on line it's working as it should.  switch illuminates in the "on" position only and the fan rotates in the correct direction - have it set up in stock location to pull air thru the left rad..

fwiw, the max air flow of the fan is 78 CFM

should be fine as the package states "120mm highest performance DC fan" haha

anyway - i can't thank all of you enough for taking time to help me.

always good to get your opinion as usual Ralph even tho i had it done before i read your reply - hope all is well

 

this is how i wired it

http://www.oznium.com/rocker-switch/tech

Edited by ROUNDEYEHELMETHEAD
  • Like 2

Share this post


Link to post
Share on other sites

between you guys & a diagram i found on line it's working as it should. switch illuminates in the "on" position only and the fan rotates in the correct direction - have it set up in stock location to pull air thru the left rad..

fwiw, the max air flow of the fan is 78 CFM

should be fine as the package states "120mm highest performance DC fan" haha

anyway - i can't thank all of you enough for taking time to help me.

always good to get your opinion as usual Ralph even tho i had it done before i read your reply - hope all is well

this is how i wired it

http://www.oznium.com/rocker-switch/tech

Hope the single fan works for you. My single fan is 138 CFM and not enough, strictly for that push pull reason. But glad to hear it spinning! As long as you keep moving it should be alright. I am curious to see it light up though. And chance for a pic or vid?

Share this post


Link to post
Share on other sites

Nice.  OK, so the thermal marked LIGHT was for the accessory fan or whatever the accessory was.  Thanks for the clarification.

Nice small lighted rocker switch rated 10 amps, should do fine.  I probably should do this to my new to me KTM.  The thermal switches are expensive and unreliable.

Share this post


Link to post
Share on other sites

not the best pics, but here's what i got. let it idle for over 25 minutes with fan on & roxanne dint turn on the red light...

i also changed out my fresh honda hp coolant for engine ice. dunno if that stuff is magic, but between the fan & coolant it's better than it was. wiring is fugly but functional so don't judge haha

will clean it up & possibly upgrade fan in near future.

but fresh bridgestones, linkage bearings, taillight & turn signals removed and minimum gas.

wish me luck in the race please lol

 

100_1999_zpsea6c4984.jpg

 

100_2001_zpsf8549d95.jpg

 

100_2003_zps6e2ffc06.jpg

Share this post


Link to post
Share on other sites

Good luck in the race.  I'm guessing the fan will last about 5-10 minutes.  I've actually removed and sold my fan a long time ago and have never had a problem.  I think as long as your moving and motor is jetted properly it shouldn't over heat.  I use engine ice.  Can't say if it works better but none of my bikes have overheated, just keep that heavy beast moving.

Share this post


Link to post
Share on other sites

Good luck in the race.  I'm guessing the fan will last about 5-10 minutes.  I've actually removed and sold my fan a long time ago and have never had a problem.  I think as long as your moving and motor is jetted properly it shouldn't over heat.  I use engine ice.  Can't say if it works better but none of my bikes have overheated, just keep that heavy beast moving.

 

I have been running dual PC fans on my E for a couple of years with out failure.....

Use em just about every ride for slow riding and heavy traffic, been through heavy rain several times, no problem....

Share this post


Link to post
Share on other sites

fan still works. and i have no doubt it kept my engine temps down during the race. i ran the fan the entire time.

fwiw,,,it's a cheapo with a sleeve in lieu of bearings.

 

and yes,,,i know all about keeping this bike moving to not over-heat. i've owned it 10 years afterall. normal local trail riding i almost never saw the red light on standard bore. on the rare occasion i did, i would just shut it off & wait a minute.

 

what happened last time i did this race(2011) - bike idled a lot prior to race start. almost immediatley after the start it went into a technical section and there was a huge pile-up resulting in stand still traffic. my bike got hot and stated boiling out the coolant.

i think they changed the track up a bit to avoid that this year.

 

been running 434 cc for a while - perhaps that adds some heat too.

 

anyway, here's kinda an after shot. removing taillight paid off...

100_2005_zpsb1563899.jpg

 

mud shovel

100_2006_zpsaab1ee49.jpg

 

finished 5th of 24 in the C open class & 55 of 155 overall. so i guess not too bad. i had a lot of fun & i don't have to rebuild the motor,,, so was a good day!

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Reply with:

Sign in to follow this  

×