heat not working

Originally I was not getting any air unless I turned the ac on high, and was not getting any heat. I replaced the ac resistor and now getting air flow on all 4 levels. Still not getting any heat and now there is a clicking sound coming from behind the glove box where the blower is located. Any...

I feel like I have tried everything to get he fully functioning in this car and I still have come up with no answers we have replaced the thermostat, had a shop flushed out the heater core and no debris came out, coolant is filled, both heater hoses are correct temps, changed blower motor,played...