a/c odor problem

We have a 2010 explorer 4dr with a/c - the vehicle appears to collect water in the drain area of the a/c box & retains that water causing an odor. we can pull the blower out & remove water from the lowest portions of the case & it is ok for a week or so. It will, by then, have collected enough water to mold & smell again. The drain is clear. The ports in the lower portion of the case are open and clear. It appears that the right side off the accumulating area is somewhat lower than the drain area. Any information on a correction to this problem other than dismantling the lower unit & cleaning out the stale condensation periodically. does Ford offer any permanent solutions?

we took apart the lower part of the case and alot of the duct work - cleaned out the drain however it wasn't obstructed. we didn't find a cabin air filter but we did find some pine needles and blew out the system clearing any obstructions - we sprayed in some cleaner and it was good for about 2 weeks - then that same moldy odor reappeared again.