A couple of days ago, my wife noticed one of the outside units making an odd noise. Turns out the inside temp was above set point, so the outside unit was running, but the inside fan was not. I assume that the odd noise was the outside unit and coil freezing.
Upon further inspection and atttempted diagnosis, I noticed that when I turn off the AC at the thermostat, and then turn the fan to "on" from "auto", the fan seems to blow normally. However, when I set the thermostat back to cool and the relay clicks for the outside unit to come on, the inside fan turns off.
I tried switching out the thermostats, but I still get the same behavior.