HVAC AC Smell on 4th Gens?

[Mr Big]

I have a 2019 Expedition Platinum. My AC has a musty/vinegar smell every time vehicle has sat for a few hours. Tried running only the fans the last 5 mins of each ride and also running heater to dry it out, but that’s not fixing it. Floor board is completely dry - I checked under the carpet and saw no signs of moisture. Besides the elbow, has anyone identified a different root cause and solution?

The smell comes from contaminants sitting in the bottom of the box. Sometimes leaves and debris fall in there. And without using some sort of dis-infectant, the smell will not go away.
Mine had the issue. I followed another poster's instructions. Get a large can of Lysol. start the engine and shut off A/C compressor and re-circulate, set your heat to max with windows down. Keep it running for around 20 minutes. After that put your air on MAX A/C with recirculate off. Go outside and spray the Lysol in 20 second bursts down the intake on the cowl. The intake opening is near the passenger side wiper gear.
It solved my issue, but it comes back if you don't turn off your A/C and let the vehicle run for a minute or so to dry out the new moisture.

 

[JimBob77]

The smell comes from contaminants sitting in the bottom of the box. Sometimes leaves and debris fall in there. And without using some sort of dis-infectant, the smell will not go away.
Mine had the issue. I followed another poster's instructions. Get a large can of Lysol. start the engine and shut off A/C compressor and re-circulate, set your heat to max with windows down. Keep it running for around 20 minutes. After that put your air on MAX A/C with recirculate off. Go outside and spray the Lysol in 20 second bursts down the intake on the cowl. The intake opening is near the passenger side wiper gear.
It solved my issue, but it comes back if you don't turn off your A/C and let the vehicle run for a minute or so to dry out the new moisture.

Thank you. Will give this a try.