How do I connect a Fan with 2 Connectors

[DarklingGolem50]

I bought a fan and it has 2 connectors (MOLEX and Fan Connector for a Motherboard) and I am confused since my motherboard has that fan connector.

Should I plug in both or only one?

 

[canadianvice]

I bought a fan and it has 2 connectors (MOLEX and Fan Connector for a Motherboard) and I am confused since my motherboard has that fan connector.

Should I plug in both or only one?

Would you be so kind as to take a picture? There's a possibility the fan header is only designed for feedback and or control of the fan speed, but to determine this being able to see the cable pinout would be helpful.

Taking a Picture, if you need guidance:

Spoiler

Obviously, taking a picture with a camera of some sort is your first step. At this point, copy the file on to your computer, and if you wish to do so, use paint to censor anything that could be incriminating or you do not wish to be shared. Once this is done, you can find a host, for instance, imgur.com, which will host the image for free. At this point, you can either link to the image posting on imgur, or if you have a direct link, use the [img.]DIRECT URL[./img] (without the periods) tag to embed it into a post here, so we can assist. A direct link should end in a file extension, for example: http://www.imghost.com/img/cable_pic.jpg. (Note: I made that link up. It shouldn't go anywhere)

 

[ElectrO_90]

Or you could tell us the make/model of the fan and provide a web link to it.

I am guessing, you plug it into the motherboard as normal, and the Molex is for some RGB type thing.

 

[Paperdoc]

There are some fans supplied as you describe. On the end of their wires are TWO connectors. One is a standard 3-pin or 4-pin female (with holes) fan connector. The other is a male 4-pin Molex (possibly with only 2 pins mounted in it) intended to plug into a female Molex output from the PSU. This allows you to plug in either ONE of those, BUT ONLY ONE! Do NOT connect both to their respective power sources.

If you connect to the PSU Molex source, the fan will run full speed all the time, and you cannot measure the fan's speed. If you connect to a mobo fan header instead, you MAY be able to control the fan's speed, and you WILL be able to observe its speed in BIOS Setup or with software tools. Whether you can control the speed depends on the match of fan type to header capability. MOST fans with these two connectors are of the 3-pin design; that is, the motor has 3 wires (Black, Red and Yellow) from the fan to the connectors, and the female fan connector has 3 holes. That fan design can have its speed controlled ONLY by a header that uses the older Voltage Control Mode (aka DC Mode) to control its fan; PWM Mode cannot do that. So, if that's your fan type, look in BIOS Setup for the header you plug it into and check whether you have the option to set that Mode in the header's configuration.

 

[madmatt30]

Use one connector only !!!!

If you're plugging straight to a board header with the smaller a or 4 pin DO NOT connect the Molex to the Psu aswell!!

It will short the board headers out & can physically damage the motherboard.