Confused on how to connect Case Fans to PSU

[XeonZephos]

I'm really confused as to how I'm supposed to connect 2 case fans to my power supply. I have an RM750i PSU. I'm also confused as to what molex are exactly.. I've ready looked it up but am having trouble still.

The case fans are Silverstone with 3 wires (them being red, black, yellow)

Note: I know nothing in regards to molex connectors, and fans

 

[XaveT]

Molex connectors look like this:

It sounds like the one you have is like this:

They usually plug in on the motherboard, look for case fan connectors. What motherboard do you have?

 

[XeonZephos]

Molex connectors look like this:
https://upload.wikimedia.org/wikipedia/commons/thumb/1/1e/Molex_male_connector.jpg/220px-Molex_male_connector.jpg

It sounds like the one you have is like this:
http://www.quietpcusa.com/images/products/galleries/fullsize/kazemaru-2series-fan-3pin-connector-full.jpg

They usually plug in on the motherboard, look for case fan connectors. What motherboard do you have?

I have a GA-H170M-DS3H motherboard

 

[XaveT]

Hmm. Looks like that motherboard only had one fan port on the motherboard. I've circled it here. (Don't be worried that that SYS_FAN has four possible pins. It can have 3 or four, the way the plug is keyed will show you how to put it on and which pins)

So you'll either need a Molex to fan converter:

Or a splitter

 

[XeonZephos]

With the second option I wouldn't need the molex connectors? I would only have to connect the fans to the splitter?

 

[XaveT]

That is correct. You just plug the single end to the board, and each tail into a fan. You will lose PWM fuction (speed readout) but that would be lost on the Molex option too. I'm surprised that motherboard only has a single fan header, but what can you do?

 

[XeonZephos]

That is correct. You just plug the single end to the board, and each tail into a fan. You will lose PWM fuction (speed readout) but that would be lost on the Molex option too. I'm surprised that motherboard only has a single fan header, but what can you do?

I've connected it to sysFan and I excluded the outermost pin so that the female and male connectors connected with the top latches attached.

When I turn on the computer the GPU fan turns on and the CPU fan turns on, however, the GPU fan slightly turns on for a second and then stops moving as well as the case fans.

My PSU is the RM750i I think that the PSU fan will only start moving once it reaches a certain temp so i'm not too woried, but i'm not sure whether the fans are supposed to move once the PC starts up

Thanks for your help!

 

[XaveT]

Eh, I'd watch the GPU fan and make sure it does turn on when it's needed. If it's a modern card it may not until you put some load on it.

The SYS_FAN header has four pins, with a plastic key on the top (right in the picture), and you've plugged it in to the front (bottom on the picture) three right? There should be an indent on the top of the plug that the little gray part (right under the text _FA in the picture) it should fit snugly into.

Perhaps look at your BIOS, the fans may not turn if they aren't enabled? Weirder things have happened. I hope you get it all sorted out!

 

[XeonZephos]

Eh, I'd watch the GPU fan and make sure it does turn on when it's needed. If it's a modern card it may not until you put some load on it.

The SYS_FAN header has four pins, with a plastic key on the top (right in the picture), and you've plugged it in to the front (bottom on the picture) three right? There should be an indent on the top of the plug that the little gray part (right under the text _FA in the picture) it should fit snugly into.

Perhaps look at your BIOS, the fans may not turn if they aren't enabled? Weirder things have happened. I hope you get it all sorted out!

This is going to sound weird but I messed around in the BIOS and made it so that the fan speed went from Normal to Full Speed and removed the front panel and I gave the fans a boost by making the fan move by using my finger and I did this to both fans and they seem to be turning now lol. Not sure if that's how it was supposed to be.

 

[XaveT]

Eh, I'd watch the GPU fan and make sure it does turn on when it's needed. If it's a modern card it may not until you put some load on it.

The SYS_FAN header has four pins, with a plastic key on the top (right in the picture), and you've plugged it in to the front (bottom on the picture) three right? There should be an indent on the top of the plug that the little gray part (right under the text _FA in the picture) it should fit snugly into.

Perhaps look at your BIOS, the fans may not turn if they aren't enabled? Weirder things have happened. I hope you get it all sorted out!

This is going to sound weird but I messed around in the BIOS and made it so that the fan speed went from Normal to Full Speed and removed the front panel and I gave the fans a boost by making the fan move by using my finger and I did this to both fans and they seem to be turning now lol. Not sure if that's how it was supposed to be.

They can seize up a bit if they have been sitting a while. I'm not 100% certain why. Let them run a few hours at least and then see where you get next time you turn off/on the computer. Yay for it's working! 😀