Ok, here is my thing. I have a switch that came with a cathode.



I have three fans, all wired to 12v. The two fans in the back are grounded to the plug, and are wired to 12v on the DVD drive cable. The fan in front of the heat sink is grounded and wired to 12v on the dvd drive cable. The thign is that 12v is to loud. I want to wire this switch in to make it where it will switch back and froth between 5v and 12v. the problem is that I don't know how I would wire this. Can anybody help me?

Ok! I think I got it. Somebody correct me if I'm wrong.

Are you sure you want to solder to both 12v and 5v points? I think you need to solder the yellow to the 12v and ground the other. Since its being ran through the switch thats all you need to hook up. But get another opinion because I am not certain.

Well seeign as it is now to late I already hooked everything up. I soldered it the way I posted and everything seems to be workign fine. Ill let you knwo if anything happens.

The way you have it is correct, 12v one side, 5v the other side and fan voltage input on the middle. Ground doesn't have to be messed with in this case. When the switch is on one posistion you get 12v to the fan, when it's in the other you get 5v. Provided it's a SPDT switch that is ON-ON, which the one in you pic is.

You can do the "flip-side" of that as well for LEDs and have the voltage run in on the middle, then out one side to a set colored LEDs, and the other side to a set of different color LEDs. That way you could switch between the two and not have to look a the same thing all the time.

Well there you have it. I learned something new today.