I would check the wires that go from the blower motor to the circuit board. Most the time it is a thick yellow wire and it comes unplugged very easily.
Before calling the repairman, check these things first:
a) is the air filter clean? ; 2) insure all return air grilles are unobstructed c) it the unit set to "cool"?
Start by checking for voltages at the board or contactor that controls the fan motor, then check for a case ground short on the fan motor. Don't forget to check the run and start capacitors.
The fan will running off of DC voltage. Follow the wiring from the fan and use a volt meter to determine if the problem is the fan or the AC to DC tranformer.
Well you basically just check if all the buttons are working correctly and then check if the wires are pluged in correctly. Sometimes the wire just lets loose for the fan switch and we have a panic attack. But you can also just check if the power switch is on.
In the back of the manuel that came with your air conditioning unit you should clearly see some instructions for trouble shooting. If you can't find it look online.
Check to see if the blower motor spins easily with the power disconnected. If it does not, replace the motor. If it spins freely, check that the relay that supplies power to the fan is pulling in. Replace that if it is not.
