heres what u do:

turn the key to the ON position when teh motor is cool, but dont start it, turn ur AC and blower motor on. In that situation, both fans should turn on no matter what.
if they don't then its either ur fan relay or ur fan itself.

If they do come on. then its more than likely ur temperature sensor on the thermostat housing.

Also I think u can swap out the temperature sensors from input to output to check to see if it makes a difference, but not sure about that.

and forgot about the easiest thing, unplug the fan and give it direct power adn see if they come on.