Part 2 and 3 links shown down below in description explain how to unclog.

This video is intended to help new Florida (SW and Central) DR Horton owners understand the quirks of clogged drain lines and the monthly maintenance we can perform to prevent the clogs. Please for the love of Pete, don't feel the need to comment about the missing trap or I'm calling the evaporator the condenser. This was setup by DR Horton for the SW Florida region and the whole drain line is a trap. I'm just the home owner sharing the best I can, but my main point is not not use corrosive material when the drain is already blocked or it will work it's way back into the unit where I'm pointing with my finger. Always seek out HVAC experts which I'm clearly not. But hopefully if your AC is out and you are in a bind, this info can help you determine if you have a clog in the drain and point you in right direction to remove clog and get your AC back online.

If you are trying to clear out a clogged drain, make sure to following:
Part 2(setup wet vac):    • Florida AC drain , how to unclog part 2  
Part 3(Use the wet vac):    • Florida AC drain, how to unclog part 3