Need more info. Engine coolant fan? HVAC fan? What year? What model?
I had a VW Jetta that had a problem with overheating. It ended up being the thermostat had gone bad so the fan never "kicked on." A car can over heat if there isnt enough antifreeze in the radiator or a bad thermostat or if your fan isnt working properly or is bad
Either the fan is no good or the heat sensor in your radiator, that turns the fan on is not working!!
You need a new fan relay. It is on the passenger side of the firewall at the top.
Make sure that the fuse and sensor for the cooling fan are working. If these are ok then look at the fan motor, it could be bad.
YOUR TALKING ABOUT TWO DIFFERENT SYSTEMS, ENGINE COOLING FAN AND AN INTERNAL HEATING/AIR CONDITIONING FAN? WHICH IS IT?
there is a Senior that kick it the fans on it is located under the throttle body or it might be the primary fan is bad and only the second fan is working
the first thing you want to check is the fuses and relays. if those are good the fan motor, resistors, switch or wiring could be the problem.
If dust is within the fan area, it will create a the fan to move slower or activate even though your computer isnt hot. You also might find that a overheating problem will occur.
If the car is over heating then it could be that the electric cooling fan motor is not working so the fan can
Low coolant level, or a plugged heater core.
The fan relay could be bad or the fan motor could be bad.
if the fan motor isn't working, the fan motor has likely got a loose connection of some sort. if the fan does work but the reguler vents don't you might have something blocking them.