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Molex Pins to Chassis Fan Splicing

Hi!,
I have two chassis fans having +12v
with three pins. The wires are red, yellow and black
The fans are not damaged(circuits are ok) but do not run when i connect them to my molex pins.


How I Connected Them?
Red of the fan to yellow of molex
black of fan to black of molex
The yellow of fan was left open and red and another black of molex was left open.

Is that the method or i have gone wrong somewhere?

Thnaks :)
9 answers Last reply Best Answer
More about molex pins chassis splicing
  1. btw can ne1 tell me: i have 211 pts and am still a new comer? :p :(
  2. Your connections ought to be correct. Red (fan) and yellow (Molex are +12 VDC, black on both is Ground. Yellow (fan) is speed pulse signal feeding back to the mobo - no such line on a PSU Molex. On the Molex, BOTH black lines are supposed to be ground, so it should not matter which one you use. Molex red is + 5VDC.

    Just to be sure, you can use a voltmeter to verify the voltages on the Molex connector.
  3. Paperdoc said:
    Your connections ought to be correct. Red (fan) and yellow (Molex are +12 VDC, black on both is Ground. Yellow (fan) is speed pulse signal feeding back to the mobo - no such line on a PSU Molex. On the Molex, BOTH black lines are supposed to be ground, so it should not matter which one you use. Molex red is + 5VDC.

    Just to be sure, you can use a voltmeter to verify the voltages on the Molex connector.



    The fans do not work :( . Though they are fine :(
  4. Best answer
    Fan connections:

    Red : +12V
    Yellow: Control
    Black : 0V

    Molex Connections:

    Yellow : +12V
    Red : +5V
    Black : 0V

    So you take the Yellow wire from the molex and connect it to the Red wire of your f.an.

    You then take the Black wire from the molex and connect it to the Black wire f your fan.

    This will eliminate the the fan speed control though and will cause the fan to run at full speed continuously.

    How are you connecting the ends of the cables together? A crimped connection is the best connection. Simply strip away a small length of sheathing from each cable, twist them tightly together and insert them into a crimp. You then need to squeeze the crimp closed to ensure a proper termination. You can use a crimping tool if you have one, if not squeezing them tightly with a pair of pliers should do the job.

    You can get hold of crimps in most electrical stores. You should be ok if you go for the smallest size available and just explain what you need to use them for. Good luck!
  5. moody89 said:
    Fan connections:

    Red : +12V
    Yellow: Control
    Black : 0V

    Molex Connections:

    Yellow : +12V
    Red : +5V
    Black : 0V

    So you take the Yellow wire from the molex and connect it to the Red wire of your f.an.

    You then take the Black wire from the molex and connect it to the Black wire f your fan.

    This will eliminate the the fan speed control though and will cause the fan to run at full speed continuously.

    How are you connecting the ends of the cables together? A crimped connection is the best connection. Simply strip away a small length of sheathing from each cable, twist them tightly together and insert them into a crimp. You then need to squeeze the crimp closed to ensure a proper termination. You can use a crimping tool if you have one, if not squeezing them tightly with a pair of pliers should do the job.

    You can get hold of crimps in most electrical stores. You should be ok if you go for the smallest size available and just explain what you need to use them for. Good luck!



    done

    The fans do not work :( . Though they are fine :(
  6. Then a multi-meter will tell you if you have voltage there. You need to set it to the DC range and test between 12+ and 0V. This would be the yellow and black if you're testing the molex side of the connections. Obviously you're looking for a potential difference of 12V :)

    If you have a supply, chances are your fans are gone. Just out of interest, how did you cut the wires? One at a time or did you cut through them all at once?
  7. moody89 said:
    Then a multi-meter will tell you if you have voltage there. You need to set it to the DC range and test between 12+ and 0V. This would be the yellow and black if you're testing the molex side of the connections. Obviously you're looking for a potential difference of 12V :)

    If you have a supply, chances are your fans are gone. Just out of interest, how did you cut the wires? One at a time or did you cut through them all at once?


    from the molex i cut one yellow and one black one by one

    from fan i cut them all at once
    Thanks 4 replying.
    I think i'll be buying new cooler master fans and molex to fan pin adapter if available :(
  8. Requesting Mods to mark thread as solved :D though it's not :D
  9. Best answer selected by sworoop1990.
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