A few things after dropping blower to make sure squirrel cage is clean. First is the resistor - they are pretty robust. Second is the a/c amplifier - if you've ever blown a fuse involving compressor clutch coil or blower motor fault, it tends to get damaged. I think you looked at those. But... you mentioned coil was spotless. A loss of airflow while operating can be caused by icing - that would be R-134 leaking anywhere and system pressure is low. I like to see 33-35 psi on the low pressure port during operation If you find low air flow is only with damper set full fresh air, but recirc is normal there is a mechanical obstructon on the inlet.