1st time this yr going ac to heat. Nordyne elec furance mod E3EB-020H. HUMMING & CLICKING from inside the furnace, blower working, blows hot, click blows cool, click blows hot, is this from the furnace being off all summer, and restart. What may be things I can check. Is this normal?

A relay, limit or sequencer is causing the unit to cycle on and off. Make sure air filter is clean. Make sure the thermostat is turned up enough to keep the unit running. The hum is probably from the low voltage transformer. You might check the transformer to be sure it is putting out 24 volts.