My condenser unit oustside works but I get no air flow inside. When selecting the fan only switch(thermostat) for the air handler/evaporator to turn on all I hear is a clicking noise. My Central Air was working fine but then iced up due to low on frion. It has done this in the past but after defrosting the air handler/evaporator coils you can once again fell the air flow.

What could be the reason my air handler/evaporator for not enagaging and spinning the fan blades?

What are some trouble shooting steps I can do to seee what is wrong?

Look at the control panel on the air handler. Should show you a fault code or could be a bad motor or a bad capacitor.