My a/c quit because the drip pan was full. There is an overflow sensor that shuts off something when the water gets too high. Then the coil, which is frozen up, thaws and it overflows.
I could get it running again by bailing out the drip pan
There's two pans in the system. One is internal to the evaporator unit and is supposed to drain properly.If it is not draining properly cold water will accumulate in the bottom of the unit causing condensation to form on the underside of the unit.
This condensation will then drip into the pan below and if something isn't done to fix the problem it will fill up.
The drip pan often is not plumed for drainage since it's the only way you would know there's something wrong with the system.
OP,I would think if the pan is full then the main evap unit is not draining properly.