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4 Pin Molex Connector With Only 3 Wires

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Amadeus Kota

New Member
Joined
Mar 1, 2016
I have this Molex power connector for a fan and they usually have 4 wires. After a quick research I understand there's a yellow and red wire for 5V and 12V, then 2 black wires for grounds. The one I have has only 1 ground and I'm wondering whether that's a problem. It's currently connected to a fan with 4 wires. I can't seem to find an answer to this, so would anyone here be able to help? Greatly appreciated! :)
 

Automata

Destroyer of Empires and Use
Joined
May 15, 2006
Can you take a picture of what you mean? A fan connected to a molex connector should only require 2 wires.
 

ATMINSIDE

Sim Racing Aficionado Co-Owner
Joined
Jun 28, 2012
If the fan has four wires, it most likely has PWM capability.
Why not plug this in where you can control the speed instead of running it at full tilt?
 

trents

Senior Member
Joined
Dec 27, 2008
Actually, you only need two wires: one for power and one for the ground. If the colored wire is red and the position sequence of the red wire has not been changed (i.e., if it is the same place as the red wire of the lead coming from the PSU) then the fan will be getting 5v. This is a common way of slowing down a loud fan to make it quieter. Works fine if the fan has a low enough impedence so as no to stall out. If the colored wire is yellow then he fan will be getting a full 12v.
 
OP
A

Amadeus Kota

New Member
Joined
Mar 1, 2016
20160308_122600.jpg

Apologies for the late reply. A lot of things came up and I was unable to return to this for a number of days.
Here's the photo of the connector. As seen in the picture, from right to left there is a yellow wire (12V?), a black wire (ground?), a red one (5V?), and the last slot is empty. I find this layout strange. Isn't the red wire where a ground would normally be found?
The fan has 4 wires, but it's just on the side panel and I don't have a fan speed controller, so fan speed control doesn't really matter here as long as it's generating enough airflow.
 

Blaylock

"That Backfired" Senior Member
Joined
Jun 5, 2013
Location
Go Blue!
Something is fishy there. Can you post a pic of where that white molex connects or runs to the fan? The red (5v) line is connected to ground.
 

jaymz9350

Member
Joined
May 13, 2006
If the 5v line is connected where the ground should be that will make the fan run at 7v.
 

Blaylock

"That Backfired" Senior Member
Joined
Jun 5, 2013
Location
Go Blue!
I'm pretty sure you skip the ground and ground the fan to the 5v line.

Edit: like this
7v.jpg

Re-Edit: This looks useful
D-Type-4-Pin-IDE-male-to-4-way-12v-5v-7v-Power-Connector-font-b.jpg