Auto Parts: 1995 mercury mistique engine fan, coolant temperature sensor, radiator fan motor

Question
my engine fan isnt working and i wanted to know if the coolant temperature sensor and the engine fan work in sync to keep the car cool. does the sensor give the fan the que to come on and cool the engine. If not will i have to buy a relay switch for the fan. trying to find a less expensive alternative instead of buying a new fan if nothings wrong with the old one.

Answer
    I know it doesn't make sense, but sometimes the coolant temp sensor on a Ford can continue to provide the necessary information to the computer without properly operating the fan.  However, the most likely failure is that of the fan relay.  To determine if the radiator fan motor is bad, unplug it and run a pair of jumper wires directly from the battery to the terminals on the motor's side of the connector.  If this fails to cause the motor to spin, then the motor is bad.  Take it out and test it the same way on the bench, just to be double sure.  A new one is about $90, and well worth it since it keeps your engine from blowing up.  If the fan motor seems to work, then buy a new relay.  It isn't terribly expensive and will probably fail soon, anyway.  While you're at it, check the related wiring and make sure nothing is broken or disconnected.  I know it seems like a lot of money to fix the fan motor, but the car has given 14 years of good service, it's entitled to the odd treat now and then.