It's probably something simple? famous last words eh!
I presume you think the fan is causing your problem, somewhere, usually on the radiator or bottom hose you will find the temperature sensor which works the fan. Take off the plug and check the wiring for power, if none check wiring and fuses (some cars need ignition on some don't) When you have power you need to join the terminals in the socket together temporarily, if the fan starts up the temp sensor is faulty. If not, power up the fan directly from the battery, if the fan works the sensor is faulty if not it is the fan motor that as gone or seized it may not have come on all winter and may be stuck.
You could also check the sensor in boiling water but you will lose your anti-freeze that way.
There could be other problems but sort the fan first and let us know if need be.
