I have no airflow from my registers. My compressor is running and my AHU is running. Any idea what the problem could be? I have shut the unit off for now. The problem exists on heat and cool and fan only mode.

Sounds like it could be the blower motor is not working. It could be a relay but since it is doing it in heat and cool and fan only mode I would suggest more than likely the motor. Did you have a burning smell at all when you tried to operate the unit?

Open up the air handler and watch the blower when you hold in the door switch. If nothing happens, then it maybe the relay. Since most blowers are direct drive now, if the motor runs, the blower should unless it is loose on the shaft. If the blower runs and you don't get air out the vents, you must have a major duct problem.

Thanks... I think the unit was froze up. When I went back outside to check the compressor the ground is wet just under it... also the pipe inside was dripping. Not sure why I had no airflow before since the motor was running inside and out. I do have cool air right now. I will have to figure out WHY the unit froze up... but for tonight we are cooling.

If the inside coil frosted up, it could block the air flow.

A/C's freeze up due to low air flow (filter?) or low on refrigerant.

If the blower was working I can only think of two things to cause the unit to freeze up if you have kept your filters changed. 1. Low On Refrigerant 2. Stuck Contactor. If the outside unit still runs when you turn the thermostat off it is the contactor. Should it feeze up again I would check freon level.