Need help with wiring fans.

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bimmer01

[H]ard|Gawd
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Jun 29, 2004
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I just bought a few fans online and it only came with 2 wires (red and black) with the 2 pin connector.

My plan was to convert them to regular 4 pin molex connectors.

So i did some wiring last night and connected it to a molex connector, red and black.
So my molex connector only has 2 wires connected to it.

When my fan turns on, i feel like its running on the lowest voltage, 7V maybe??
How can i increase the voltage without using a fan controller?
Any ideas?
 
Yes, you need to attac your red wire into the molex's yellow wire.
 
How I understand it is this. The red wire is 5V the black next to it is its ground. The yellow is 12V its ground is next to it.

So...it appears that you wired your fan for 5V operation.

To change it to 7V: "you can simply use the voltage difference between the +12V and +5V lines to power your fan with 7V: Connect the fan's + wire (usually red) to the power supply's +12V wire (yellow), and the fan's - wire (usually black) to the power supply's +5V wire (red)."

http://www.heatsink-guide.com/content.php?content=connector.shtml


Or you can use 12V by connecting + to the yellow wire and - to black. Hope that helps. :)
 
gotcha, so i wire my red fan wire and attached it to the yellow molex wire, thanks

so for the molex side, only 2 wires/pins (yellow and black) rite?
 
I'm not sure what u mean, but yeah if you take out 2 pins that will work fine. :)
 
bimmer01 said:
gotcha, so i wire my red fan wire and attached it to the yellow molex wire, thanks

so for the molex side, only 2 wires/pins (yellow and black) rite?
Click to expand...


yup you got it m8.
 
On the molex:
Red = +5VDC
Yellow = +12VDC
Black = GND

On the fan:
Red = +12VDC
Black = GND

So simply wire black to black, and red (on the fan) to yellow (on the molex).
 
^_^ Yep. :)
For some reason many fans come with a red power lead instead of yellow.
 
From what I understand, red is used to indicate the primary operating voltage. So a 12V fan would use red, since 12V is the primary operatinf voltage.

Motheroards and disk drives mainly run on 5V, so the 5V gets to be red, with yellow (12V) being the secondary voltage.
 
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