Over time wiring can break down or weaken which causes this problem.
Roof fan stopped working.
If there is any damage to the belt replace it with a new one.
Roof vents with fans like the maxxfan roof vent w 12v fan ma00 04000k do not have a fuse anywhere in the fan itself.
Remove the outer casing of the attic fan and check to see if the belt is sagging cracked worn or broken.
By pulling in cooler air a whole house fan reduces or eliminates the need for air conditioning.
How to troubleshoot a whole house fan.
Fan motor runs but not the blades.
Electricity to fan not working if after flipping the breaker and testing a couple different outlets you discover that the issue is electric rather than in the fan itself you will likely need to call in an electrician to take care of it.
If the motor is working but the fan blades are not moving the problem may be the belt.
You will want to use a circuit tester like ptw2993 to see if there is power getting to the fan.
Your attic fan may not be turning on because of an electrical problem like a tripped circuit breaker a blown fuse or a bad connection.