On 6 Nov 2006 07:17:59 -0800, "rbt"
<robertbruceshaw@hotmail.com> wrote:

>The switch would break that, or the ground, not
>the red wire to turn the fan(s) off.
>
>is the opposite tru in all states...
>
>The switch would make that, or the power, not
>the black(ground) wire to turn the fan(s) on
>
>no wonder im frightened of it... that how ive been seeing it
>


You'd want the 12V, power lead from the PSU wired to the
middle switch contact (let's call that contact #2).

Wire the fans' positive power leads to switch contact #1 (or
contact #3, pick one or other other and wire them all up to
the same contact).

Wire all the fans' negative, grounds to the black PSU Gnd
wire, they are not switched.

You "could" do it the opposite, switching the ground instead
of the power but there is no reason to do it in your
situation.