[jnaas2]

Turn the power off to the fan and check with a voltage meter to make sure the power is off, if it is you can test the switch by setting the meter to ohms reading and touch the black and red probes to the 2 screws on the switch and see if there is resistance or not. If the meter reads 1 there is infinite resistance, if you flip the switch and it shows little or no resistance then the switch is working right. You can test the thermostat in the same way by changing the setting on the thermostat. The power will go thru the switch first then the thermostat and finally to the fan, you always break the power supply so if your brave you can check the switch and the thermostat with a voltage meter and the power supply on, but this isnt recommended if your not comfortable working around live wires. Put the black probe on the white wire and check the screws on the switch and see if there is power at both screws, if there isnt flip the switch and then check, follow the same procedure for the thermostat. If you want to save some time check if there is power at the fan if there is then you have a bad fan motor