Can I join a 4 pin fan on to a 3 pin connector?

[Sir Topham Hatt]

I have some new 4-pin fans.

My PC only has 3-pin (which actually only has two pins) connectors, which are just converters from a molex connector.  There's about 5 of them, so I don't mind butchering the plastic to fit the new fans but is this possible?

If so, how do I know which pins need to be connected?

Not bothered about PWM as I haven't touched the speed of the fans since getting this case anyway.

 

Sorry no photos, I'll grab some later today.

 

The fans are Be Quiet Silent Wings 3, I don't know what the PSU is (but there aren't any molex > 4-pin connectors in the box), the case is a fractal design mini c (taken out the FD fans that came with it in an effort to reduce the sound to likely the same sort of volume as before making all of this moot anyway!).

[Xahid]

4 pins means, Fan speed can be controlled by software, 3 Pins does not have that option,

usually there is a boundary separator on the connector for 3 pins so you can easily fit 4 Pins connector on 3 Pin junction and vice versa.

like in this picture, so you can easily left the 1 pin.

[Sir Topham Hatt]

Managed to find my photo:

 

 

Think I'll have to butcher two of the connectors to make it fit but you can see here there's just the two cables to each one anyway.

Although from another hobby, seems easier to cut the plug off and solder the wires to a new male pin to put into the female fan plug.

[Xahid]

On 30/09/2021 at 12:15, Sir Topham Hatt said:

Managed to find my photo:

 

 

Think I'll have to butcher two of the connectors to make it fit but you can see here there's just the two cables to each one anyway.

Although from another hobby, seems easier to cut the plug off and solder the wires to a new male pin to put into the female fan plug.

That does not look like Fan's connectors, what kind of Fan is that? is it casing fan?

[Jim K Global Moderator]

yea, it should work.  Just match your Ground / 12V/5V ... you'll just have to cut the lip (furthest away from the wires) to make room.  Seems kinda janky ... but whatever.   

[Sir Topham Hatt]

On 30/09/2021 at 11:35, Xahid said:

That does not look like Fan's connectors, what kind of Fan is that? is it casing fan?

That's an adaptor that is fitted to a modex connector from the power supply.

 

The little connectors are 3 pins (although actually just 2), which were connected to two case fans.

 

Motherboard has one connector for a 4 pin fan but I have three fans to fit so need to change some of the little connectors (in the photo) or buy another one that is already fitted (but post around here can be a little off... covid and all that).

[Sir Topham Hatt]

On 30/09/2021 at 12:08, Jim K said:

yea, it should work.  Just match your Ground / 12V/5V ... you'll just have to cut the lip (furthest away from the wires) to make room.  Seems kinda janky ... but whatever.   

This is where my knowledge breaks down... I have a multimeter but don't really know how to use it to find the right connectors.

 

I guess I touch the red lead to one of the pins from the molex, and see if it jumps to 12v? And the black lead needs to go to the other pin on the molex? 

[Jim K Global Moderator]

Probably be best to get a SATA (or Molex) > 4 pin adapter ... or even a small fan hub.

[Sir Topham Hatt]

Just to bring this to a conclusion, it was easier than I thought.

Snipped off one side of the connector (on the molex adaptor) and slid my fan connector on.  Works fine.

 

Whether it was worth the effort, I'm not sure 🙃

[Matthew S.]

Just an an aside, might be wise to cut down on the wire clutter and get yourself something like this: https://www.newegg.com/p/1YF-0016-00050?quicklink=true 

[Sir Topham Hatt]

On 06/10/2021 at 23:42, Matthew S. said:

Just an an aside, might be wise to cut down on the wire clutter and get yourself something like this: https://www.newegg.com/p/1YF-0016-00050?quicklink=true 

Wish I could make use of one!

 

Even though my PSU is supposed to be modular (it sort of is), there's still a lot of cables that are lying around doing nothing as they're permanently wired in to it - I only have one SSD and one HD but I have wires to have about 6!