Radiator fans

I have to fans on my 2006 Grand Prix
when the temperature reaches 3/4  
the fans still will not come on  All 3 of
the relays are good all of the fuses  
are good I put 12 V to the motors
themselves outside of the car and
they worked fine I'm just looking for
something else that is obviously
connected to the fans that would
turn them on once the engine
reaches a certain temperature any
advice is welcome I know with these
outrageous mechanic prices we car
we owner/home mechanics must
stick together and help each other I
have replaced a timing belt water
pump  serpentine belt head gasket  
but I have no idea when it comes to
the electric part of engine repair I am
happy to help on any of the repairs
I've made just hope someone can
help my thanks