first thing is turn on the ac and check the fan wire to see if there is juice in the positive wire. And check the ground to see if it is good with a multimeter. If you have the tpi set up there should be two relays on the right side of the radiator those could be bad. you need to check them and see whats going on over there. Does your fan come on at all........ so fan could be bad , relays' could be bad, manifold coolant sensor could be bad. Also disconnect the wire at the fan switch located on the right side of the block ground that wire out if the fan comes on then you know your thermal switch is not operating correctly....

I have a 1 fan set up but I am assuming you have the two fan set up

hope this helps
Kenny