Wiring Case Fans to a switch

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SilentLunatic

Gawd
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Oct 19, 2002
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I plan to pick up a few LED rocker switches to mount in the front of a 5.25" Bezel. My question is, do you wire the Red wire from the fan to the switch then to the motherboard and ground the wire from the switch to the case?

Also, does flipping the switch on not cause a voltage drop?

Thanks

 
There are two power wires for the fan; a red one and a black one. Cut either one somewhere along the line, and (assuming you have a two-pole on/off switch) connect one side to one of the poles of the switch and the other side to the other pole. It doesn't matter which wire you cut, and it doesn't matter how you orient the switch because it does not have any polarity.

And the switch will not cause a voltage drop.
 
why not just get something like this?

i have one, i did the resistor mod to dim the LEDs, or you could just disconnect them completely. i bought one 3 1/2 years ago and still use it today...

is there a particular reason u want switches?
 
do you wire the Red wire from the fan to the switch then to the motherboard and ground the wire from the switch to the case?
Click to expand...
It likely would work but for a lot of reasons too long to go into its not a good idea to use the case ground this way.

Find/use a molex connetor from the power supply, The 4 pin type used to plug into your CD/DVD player. If you dont have an unused one (buy a cheap extension or Y splitter and hack it up for the end you need to plug your "fan power" into the existing power supply molex) or you can splice into the wires with small wire nuts, solder and heatshrink etc. etc. depending on your skill level.

Now the big deal - the red wire on the fans just mean postive and most likely 12V for typcial comptuer fans. YOU CANNOT ASSUME THE COMPUTER POWER SUPPLY RED WIRES ARE 12V - THEY ARE NOT !!!

ON the connectors coming from your powrer supply the YELLOW wire is the 12V (red is +5 on computer power supply) so if you connect the red fan wire to the red power supply wires the fans will run very slow if they will run at all.

So it is red from fan to yellow of power supply for full speed fans.
 
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