I checked the wire connections and checked my fan with a hot wire. They both checked out to be ok, but my cooling fan will not come on!

What makes the cooling fan turn on and off and where is it located?

Its like a car radiator, it has a thermostat in there somewhere... but its probably electronic. If you have a lot(or too much) antifreeze/coolant in the radiator, it may not be getting hot enough to switch itself on. Goodluck.... let us know what you come up with.

It will have a sensor screwed into the motor with two wires going to it, the wires will lead you back to the fan.