At the beginning...
Check the coolant level. (Done)
Check the cooling system has no obvious leaks/no puddling. (Done.)
Ensure the reservoir pressure cap is secure.
Check the fan fuses are good. Underhood fuses 2 and 6.
Check the fan relays are good. Underhood relays 15 and 16.
Check the fan(s) spin freely by rotating them by hand.
With the car on, turn on the AC, if the car is so equipped. If both fans run, the fan resistor is likely faulty or the wiring harness to the fan resistor is burnt.
Check the fan wiring harness for breaks, burns or chafes.
Check the thermostat operation. (Ensure it opens.)
Test the Cylinder Head Temperature sensor/wiring.
If common experience is anything to go by, your fan resistor or connector is likely burnt.
http://www.focusfanatics.com/forum/showthread.php?t=114907