2-wire case fan

[rwatki]

I need to replace a bad 2-wire fan with a new one, and all the modern fans are 3 or 4 wires. Can I just connect 2 of the wires from the fan to the MB and leave the 3rd (or 4th) wire just hanging or does it have to tie to something to work properly? Basically, I know the fan will run full speed, but that's all the MB knows, is ON or OFF.
Put another way, how can I get the 3 or 4 wire fan to run in either ON (full speed) or OFF mode using just 2 wires?

 

[geofelt]

The two wires red and black are plus and minus 12v. It will run full speed.
The yellow wire is a speed sensor wire. Most motherboards have three pin connectors to receive the speed control info.
If yours does not, no harm, and the fan will still operate at full speed.

 

[rwatki]

The two wires red and black are plus and minus 12v. It will run full speed.
The yellow wire is a speed sensor wire. Most motherboards have three pin connectors to receive the speed control info.
If yours does not, no harm, and the fan will still operate at full speed.

Ok, ill give that a try. Just leave the yellow and blue disconnected and only use the red/black.

 

[Andy_114]

I need to replace a bad 2-wire fan with a new one, and all the modern fans are 3 or 4 wires. Can I just connect 2 of the wires from the fan to the MB and leave the 3rd (or 4th) wire just hanging or does it have to tie to something to work properly? Basically, I know the fan will run full speed, but that's all the MB knows, is ON or OFF.
Put another way, how can I get the 3 or 4 wire fan to run in either ON (full speed) or OFF mode using just 2 wires?

I have a similar problem with my computer case fans http://angelsrecipes.gohuff.com/computer-case-wire/ any ideas guys black and red wires on the left black wire has come loose any idea how it goes back in?

 

[madmatt30]

That's a molex fan connector ??
Red is on the end (12v)
To run the fan full speed you can fix the black wire to either of the middle 2 pins- they're both ground.

If you want to run it 2/3rds max speed fix it to the opposite side of the block to the red wire (right on the end)

Either way you can't break anything (just DONT short the 2 wires together)