3 Case fans not working, please help.

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ask83r

Junior Member
Oct 24, 2014
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Case: https://pcpartpicker.com/part/rosewill-case-galaxy01
Motherboard: https://pcpartpicker.com/part/asus-motherboard-z97prousb31ac

I have three fans to hook up and here are the parts they look like
http://puu.sh/kprqD/3ea6a64488.jpg (no. 1 and 2)
http://puu.sh/kprrF/1444d87796.jpg (no. 3)

So I plugged this into channel fan
http://puu.sh/kprI8/c741ccc7cb.jpg

and plugged no 1 and 2 into it like so
http://puu.sh/kprsd/a1a7e3c624.jpg

no 3 still is not plugged in but when I turned it on, non of the fans work except my CPU fan (which I won't even include in the post since it's working)

Any ideas? There's no 3 prong pins on the board to plug no 3 into anyways.

Thanks!
 

SlitheryDee

Lifer
Feb 2, 2005
17,252
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I believe you can plug the 3 hole fan into a 4 pin plug. The plug on the motherboard should have a slightly offset plastic tab that fits into a groove in the fan plug to show you which 3 pins to plug it into.

The other two case fans probably won't work with the motherboard ports at all. The fact that they have a molex plug indicates that they are intended to be plugged directly into one of the power supply cables. That means you can't control their speed through the bios, but fans like that sometimes have a switch that allows you to adjust the speed between 2-3 settings. I'd check for that.
 

bigboxes

Lifer
Apr 6, 2002
41,612
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I believe you can plug the 3 hole fan into a 4 pin plug. The plug on the motherboard should have a slightly offset plastic tab that fits into a groove in the fan plug to show you which 3 pins to plug it into.

The other two case fans probably won't work with the motherboard ports at all. The fact that they have a molex plug indicates that they are intended to be plugged directly into one of the power supply cables. That means you can't control their speed through the bios, but fans like that sometimes have a switch that allows you to adjust the speed between 2-3 settings. I'd check for that.

Agreed. If you have only a molex connector for the fans indicate that they are not PWM fans. As SlitheryDee said, look for a switch connected to the fans to adjust fan speed. If not, you'd have to use a fan controller to adjust the fan speed.
 

Drako

Lifer
Jun 9, 2007
10,697
161
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There are 4 4-pin chassis fan connectors on that motherboard. The 3 pin fan should plug into one of those. Note that these connectors are for both 3 and 4 pin fans, as Slithery pointed out.

You have to set up the function of the chassis fans in the BIOS. Go to AdvancedMode->Monitor->ChassisFan 1/4 Control in the BIOS.
 
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Paperdoc

Platinum Member
Aug 17, 2006
2,442
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Unplug all those fans at once!

No. 1 and 2 are designed to be plugged into EITHER a 4-pin Molex PSU output OR a mobo 3-pin fan port. You have plugged each into BOTH locations! This means you have connected a PSU 12VDC source into what should be a different output from the mobo. This could damage the mobo fan port, so disconnect now.

Next, try connecting fan No. 3, which apparently has only a 3-pin fan connector, to one of the mobo CHA_FAN (that's short for Chassis Fan) ports and see what it does. It should run at full speed all the time. If it does, that tells us two things: the port is working (probably) and is set to PWM Mode.

Your mobo's four CHA_FAN ports can be set to control properly either 3-pin or 4-pin fans, plus there are a few other options to set. Since all your case ventilation fans are 3-pin type, you must set the ports that way. I think you configure each CHA_FAN port separately. See your manual, Section 3.7, pp. 3-48 through 3-51. Go into BIOS Setup to the Advanced screens, then to the Monitor panel. Scroll down to Chassis Fan 1 Speed and see Manual p. 3-50. Make sure it is Enabled and set to DC Mode. You get to select which temperature sensor governs the Chassis Fan, and I suggest the "MB" (motherboard sensor) option. You can leave the fan Low Speed Limit alone for now, but this is where you come if a large fan is running slow all the time (doesn't need high speed) and generating nuisance warnings. Set the Profile to "Standard" to allow the mobo to exercise automatic control. Make these adjustments for all the CHA_FAN ports, then SAVE and EXIT. Now your test Fan No. 3 should still be running, but probably at a slower speed now that the port knows how to control it.

If that works, plug those No.1 and 2 fans back in, on empty CHA_FAN ports, and they should work, too. Do NOT plug the large male 4-pin Molex connectors from those two fans into anything.
 
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