You don't say what vehicle or what type of fan so: Viscous Fan, fluid leaked out of coupling. Electric Fan, Fan motor burned out or brushes worn out. Fan relay failure, Fan Fuse failure, Temperature switch, in the radiator? failure (very common). With the ignition on short out the switch connector socket and see if the fan starts. If it does it's a switch fault. If not, start with the fuse then check the fan relay before condemning the fan.
You probably have a bad coolant temperature switch, this are fairly cheap and easy to install.
you might have to replace your water pump, coolant, or coolant fan switch wich is located behind the power steering fluid. If none of those work you might have a vacuum leak
The coolant fan may have a blown fuse. The electric motor, on the coolant fan may be not working. The ground wire on the cooling fan may be corroded or loose.
Defective radiator cap?Fan temperature sensor defective?
Check your radiator fan switch and your fan switch coolant sensor .
try turning on the fan switch in the car
Regular bike coolant will work just fine. That is what I use.
Blown fuse, bad fan motor, defective thermal switch or a bad fan relay. Or check the coolant temp sensor.
I have seen this before more than likely your coolant sensor has a internal short and needs to be replaced.
Ok what are the fuses in the engine fan No.1, fan No2, and fan No3 , what are the for.
Low coolant, failed water pump, restricted radiator, inoperative radiator fan, thermostat,
If the coolant fan does not operate on a Chevy Corsica, it is likely that a fuse is out. There could also be a mechanical defect in the fan or wiring.