Bill fans if I remember right fire up when grounded (meaning that they'll come on when the thermo switch makes a ground. You can try a couple of things to better help out your chance of getting a good reply and diagnosis.
1. Does the fan come on when the ac is on?
2. Fuses fine (sorry but K.I.S.S!)
3. Can you run a ground to the engine from the neg (one that goes to the coolant temp switch) and do they turn on? Don't quote me but I think the thermo switch is on the return line to the radiator. If they do then you likely have a bad coolant temp switch or bad wiring (the wiring gets horribly tarnished coming out of the thermo switch. First thing I'd try though if it turns on when adding a ground is pulling your coolant temp switch and lightly cleaning it with some fine sandpaper then reinstall. Remember to have the car to the on position though when trying it!
