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4 wires fan to 2 wire Answered

Hi guys, i need your help!
I have an Enermax 12cm fan (EB122512H), i need to plug it to a 12v DC power supply but i don't know how to wire it;
The fan has 4 wires (yellow, black, white, red) but the power supply has just two wires.
could you help me?


This is an exhaust fan of a Lenovo E49. I am confused which 2 wireshave to be connected to the battery to give power. Plz answer ASAP


Google brought me here. I found the same fan in some old broken PSU. Did not work at first, but don't give up yet fellows :-)

Yellow +12V

Black GND

White rotation sensor

Red PWM input

Since this product is not meant to be replaced with standard components, Enermax omitted the pull-up resistor on the PWM input. Simply connect Yellow and Red to +12V and the fan will run.

i have tried all the possible configurations but it doesn't work :\ when i try black and red the fan moves a bit for a tiny instant but it stops immediately.... i think it is broken because it starts to stink like a burnt circuit

That smell might be the smell of magic smoke,


There's not much the Answers forum can do for you if your fan has released its magic smoke. ;-)

If this is the case, I am hopeful you will find another fan, and hook that one up correctly next time.

Here is a project idea for broken PC fan. Assuming the windings and magnets are still good, you can make a very tiny alternator generator.


That is, if you can take the fan apart without breaking it, and also manage to rewire, de-solder, re-solder, the stuff connected to the fan's windings.

I think that might be a PWM fan, and this page,


sort of explains the pinouts for this kind of fan. The four wires are: ground, +12V, PWM input, and speed sense output.

I think if you can figure out which two wires are ground and +12V, and leave the other wires open, i.e. not connected, then the fan will turn at full speed.

If I had bothered reading the comments I woudl ahve seens yours and moved on


Can't sake with 100% assurance, but see


For an interesting tidbit.

"The 120mm Enermax branded fan (EB122512H) is controlled to rotate between 450 rpm and 2,000 rpm depending on the ambient temperatures. It is a 9 blade design and incorporates dual ball bearing and is rated for 0.30A at 12V."

It could be the two extra wires are for measuring fan speed (my fav) controlling speed, or it could be a stepper (although that seems overkill for a power supply fan)

sure enough...a quick search of google images for Enermax EB122512H presents this "insitu" image, which answers it handily:


3 years ago

Use +red and -black.


Yellow on +12V
Black on Ground
I suspect the other two are for spped control/light.

if i just use the yellow and the black, the fan doesn't run... is it possible to bypass the speed control?

Hmmm, unusal but try red and black.
Would mean Yellow is used for the speed sensing.