Wiring a 4-pin fan direct to 12v DC

Hi folks,

If I want to wire my 4-pin Coolink SWiF2-120P PWM fan (yellow, black, green & blue wires) direct to a 12v DC source, do I connect the yellow lead to the 12v positive, the black to ground and ignore the blue and green signal leads?

I have searched all over and found some confusing (at least for me) information.

Thanks,
Jim
Reply to rockethead26
16 answers Last reply
More about wiring direct
  1. I'm not sure what the colors mean on your fan or what the pinout is. Usually you've got say a Yellow, Red, and Black. I normally would wire the red and black to positive and neg respectively and ignore the yellow altogether.

    If you end up wiring more than one fan though, make sure you wire them in Parallel not Series.

    Example:


    Do you have the fan-to-molex adapter for that fan or did it come with one? If so, then it's easy to figure out which ones are supposed to be on the 12v and which ones can safely be ignored. Look at this diagram:
    Reply to rwbronco
  2. rwbronco said:
    I'm not sure what the colors mean on your fan or what the pinout is. Usually you've got say a Yellow, Red, and Black. I normally would wire the red and black to positive and neg respectively and ignore the yellow altogether.

    If you end up wiring more than one fan though, make sure you wire them in Parallel not Series.

    Example:


    Do you have the fan-to-molex adapter for that fan or did it come with one? If so, then it's easy to figure out which ones are supposed to be on the 12v and which ones can safely be ignored. Look at this diagram:
    http://www.silentpcreview.com/files/images/su_1257.jpg



    rwbronco,

    Thanks for your reply. According to what I can find on the internet, my 4-pin connector looks like this:

    Pin 1 - Ground - Black
    Pin 2 - 12v - Yellow
    Pin 3 - Sense - Green
    Pin 4 - Control - Blue
    Reply to rockethead26
  3. Then I'd just wire up pins 1 and 2 and ignore the 3 and 4 pins
    Reply to rwbronco
  4. rwbronco,

    Thanks again, I'll give that a shot. I wasn't sure if the fan would run without some voltage feedback from the green wire.
    Reply to rockethead26
  5. now that's a good point, although I don't think it's necessary. I'm not sure what "sense" means in the 4-pin layouts, usually with 3 pin, the "control" is the fan speed. The motherboard reads out the temp and tells the pin to go up in RPM or down in RPM depending on the need for heat dispersion.

    I wired up some regular 3-pins in a cabinet one time for an HTPC and they had the molex connector adapter. I liked going through the molex adapter because I could change out the fans if they died/quit working without having to desolder anything or clip and resolder.
    Reply to rwbronco
  6. rwbronco said:
    now that's a good point, although I don't think it's necessary. I'm not sure what "sense" means in the 4-pin layouts, usually with 3 pin, the "control" is the fan speed. The motherboard reads out the temp and tells the pin to go up in RPM or down in RPM depending on the need for heat dispersion.

    I wired up some regular 3-pins in a cabinet one time for an HTPC and they had the molex connector adapter. I liked going through the molex adapter because I could change out the fans if they died/quit working without having to desolder anything or clip and resolder.


    Thanks again. It's funny that I'm having such a hard time finding the answer to this question. Answers given on other internet sites to similar questions by other posters were conflicted.

    I would use the molex connector, but these fans are going into a telescope that doesn't use those connectors. Soldering is just part of the deal.

    While trying to figure this out for myself, I touched the yellow wire to the red terminal on my 12v battery and the black wire to the black. What I got was a momentary spin-up of the fan that then stopped. I don't know if the weak connection formed by just touching the wires lightly to the terminals causes the temporary spin of the fan, or whether the green or blue wires need some kind of DC voltage for the fan to work.

    While I was experimenting with touching different wires to the red terminal on the battery I fried a $15 fan. I ordered another, but I would like to avoid more costly experimentation. :pt1cable:
    Reply to rockethead26
  7. rwbronco said:
    now that's a good point, although I don't think it's necessary. I'm not sure what "sense" means in the 4-pin layouts, usually with 3 pin, the "control" is the fan speed. The motherboard reads out the temp and tells the pin to go up in RPM or down in RPM depending on the need for heat dispersion.

    I wired up some regular 3-pins in a cabinet one time for an HTPC and they had the molex connector adapter. I liked going through the molex adapter because I could change out the fans if they died/quit working without having to desolder anything or clip and resolder.


    Thanks again. It's funny that I'm having such a hard time finding the answer to this question. Answers given on other internet sites to similar questions by other posters were conflicted.

    I would use the molex connector, but these fans are going into a telescope that doesn't use those connectors. Soldering is just part of the deal.

    While trying to figure this out for myself, I touched the yellow wire to the red terminal on my 12v battery and the black wire to the black. What I got was a momentary spin-up of the fan that then stopped. I don't know if the weak connection formed by just touching the wires lightly to the terminals causes the temporary spin of the fan, or whether the green or blue wires need some kind of DC voltage for the fan to work.

    While I was experimenting with touching different wires to the red terminal on the battery I fried a $15 fan. I ordered another, but I would like to avoid more costly experimentation. :pt1cable:
    Reply to rockethead26
  8. the reason that is, is because you're sending 12v to some controllers on the fan that weren't intended to handle 12v.

    This is kind of something I was referring to when I said "adapter"



    That way you could simply unplug and swap the fan for another one if it ever had a ballbearing develop a flat spot and start squealing or clicking or if it ever went out completely.

    edit: you'd simply clip the smaller black/red wires a ways back from the plug and solder/join those to the 12v lead making it easy to change out the fan if necessary
    Reply to rwbronco
  9. rwbronco said:
    the reason that is, is because you're sending 12v to some controllers on the fan that weren't intended to handle 12v.

    This is kind of something I was referring to when I said "adapter"

    http://www.shopperbuy.com/product_images/o/380/l_02334796__40203_zoom.jpg

    That way you could simply unplug and swap the fan for another one if it ever had a ballbearing develop a flat spot and start squealing or clicking or if it ever went out completely.

    edit: you'd simply clip the smaller black/red wires a ways back from the plug and solder/join those to the 12v lead making it easy to change out the fan if necessary



    Ah, thanks for the picture of the adaptor. That, indeed, would make future changeouts easier. Definitely a consideration assuming my fans will work as we expect them to with just the two leads connected.

    Thanks again for all your help!
    Reply to rockethead26
  10. Hi all, I found this post that has been useful to me! So Thank you!
    But I have a question; I have connected the same fan to an Arduino Due.
    Yellow which is the power to the 5V of the Arduino Due.
    Black which presumably is the ground to the GND.
    Now the fan starts.
    What I need is to be able from the Arduino to switch on/off the fan based on temperature.
    The only way I managed to do it is using the Blue wire and connecting to the Digital pins (like 22) or PWM pin (like 3) and giving HIGH to start and LOW to stop.
    I tried to put the yellow directly to the digital or pwm pins but it will not start.

    I do not like this because at every Arduino loop, even if I do not change any pin, I got the fan to move...
    And I do not know why.

    Thank you if You can help me more.

    Best regards,
    Camillo
    Reply to camillo777
  11. Old thread I know but incase someone else needs the info

    Wiring Diagram for black, yellow, green, blue PWM fans

    http://www.pavouk.org/hw/fan/en_fan4wire.html

    +12V to yellow
    -12V to black

    ignore sense (green) and control (blue) wires but the fan will run at max rpm without modulation so watch those digits if you playing around...

    a 3500rpm metal fan will hurt!
    Reply to rithym
  12. Hi I just wired a 4 pin fan, the yellow is possitive and the black is neggative so ignore blue and green

    I would use the molex connector, but these fans are going into a telescope that doesn't use those connectors. Soldering is just part of the deal.

    While trying to figure this out for myself, I touched the yellow wire to the red terminal on my 12v battery and the black wire to the black. What I got was a momentary spin-up of the fan that then stopped. I don't know if the weak connection formed by just touching the wires lightly to the terminals causes the temporary spin of the fan, or whether the green or blue wires need some kind of DC voltage for the fan to work.

    While I was experimenting with touching different wires to the red terminal on the battery I fried a $15 fan. I ordered another, but I would like to avoid more costly experimentation. :pt1cable:

    Reply to ComputerMaster01
  13. ComputerMaster01 said:
    Hi I just wired a 4 pin fan, the yellow is possitive and the black is neggative so ignore blue and green



    What power source did you use in your setup? I am attempting to power the standard Intel heat sink 4 pin fan with an external power supply I picked up at micro center, but am not having any luck. I connected the yellow (positive) and black (ground) wires to my power supply, plugged it in, and the fan attempts to start or "stutters" forward, but then stops. If you wait a second, it will stutter forward again, and then stop.

    My power supply Output is 12V DC 1A, and the fan requirements on the label read DC 12V 0.28A.

    Everything I've read on the internet says to just "ignore the green and blue wires" so I think either my power supply is insufficient or somehow I need to feed a signal to the PWM (blue) wire.
    Reply to APOLLO457
  14. Hello, rockethead26. 4 pin fans use Pulse Width Modulation to regulate speed - the PWM pin. Accepted voltages are TTL standarts - so, max voltage is a bit above 5V - hence your busted $15 fan. If you wanna make your fan work you'll need a 5V source and connect it to the PWM pin (100% speed). Usually you can get it from the 4 pin molex connector (don't know which color - search it.

    I must say I have not tested it yet but I found your question researching on the subject for installing a 4 pin fan on my RAID server. Here's a good documentation:

    http://formfactors.org/developer%5Cspecs%5C4_Wire_PWM_Spec.pdf

    Check page 10. Also, if you want, search for Pulse Width Modulation on the web - it's the same method used in Digital Amplifiers for audio.

    Hope I could help!
    Reply to Max_79
  15. Hey everyone.

    My fan has:
    red
    yellow
    green
    blue

    which one is which?

    Thank you!
    Sam
    Reply to sammycoop
  16. Sammycoup, that color system is NOT common, so the colors alone may not help. But IF it has a standard 4-pin female fan connector on the end of those wires, we can figure it out. A "standard" connector has on one side of it two ridges just outside the first and third pins, with the fourth pin beyond the one ridge. When this is plugged into a male mobo fan header, that header has a plastic "tongue" sticking up beside Pins 1-3, and those ridges must fit outside the tongue. That way you can only plug the fan in one way.

    Now, look again at the connector. The hole on the fan connector at one end that is OUTSIDE the ridges is Pin #4. Pin #1 starts at the other end, just inside one of the ridges. Ignoring the colors for a moment, the pins (hole) have these functions:

    Pin # 1 Ground (normally Black)
    Pin # 2 +12 VDC fixed voltage on a 4-pin fan system (normally Yellow, sometimes Red)
    Pin # 3 Speed pulse signals from motor to mobo (normally Green, sometimes Yellow)
    Pin # 4 (outside the ridges) PWM signal (normally Blue)
    Reply to Paperdoc
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