Musty mold smell in cab...tried a few things.. help!
 

So I'll try to word this to be as helpful as possible. Truck is a 2018 XLT crew cab.

-First time noticing this was about a year ago, anytime I would turn air on I was hit with a musty mold smell. It was ongoing for a few days so I was about to really dig in or take to the dealer, then it went away all of a sudden.

-Flash to now, its happening again. It was so bad on my way to work I honestly felt stuffed up and almost sick like. My nostrils had a slight burn and it was just hard to breathe. Yes, we've had a lot of rain lately.

What I've discovered:
-I read some threads and first looked into my moon roof, the wind screen doesn't appear to be wet or smell. Water does get in as designed but I'm not sure how to access drains to further look.
-I checked behind rear seat where the vent is as someone else had mentioned, and discovered a spot on the floor that is damp. Very small, maybe 2 inches. I got as close as I could and it doesn't really smell.
-I believe its AC related because if I just get in to the truck, I have no smell and the AC seems to kick it off. I recently replaced my cabin filter.

How/where should I be looking to see if its something with my AC system that doesn't involve a ton of work?

Try this for a few days and see if it helps.

About 10 minutes or so before you get to your destination, turn OFF the AC button (not the blower) and you can also turn the Recirculate button OFF so fresh air comes in. Turn up the blower a little too. The idea is to dry the moisture inside the unit which could be the cause of the bad smell.

I do this every day and no bad smell. I was starting to feel a stinky smell at first too.

Old problem discussed often.

I've seen this mentioned, should I be concerned about what's possibly grown so far though? I have also seen products or lysol being sprayed into the intake to help combat what might already be there. I definitely didn't notice it until somewhat recently. Which would be higher temps finally mid 80's, tons of rain, tons of humidity.

If you use your AC a lot and pin down if its definitely an AC problem try this:
Get some Lysol and spray it into the outside vents with the doors open, uncirculate, blower on hi.
And check the AC water drain making sure its not plugged.

To prevent this from happening in the future, turn off the AC maybe a couple miles from parking with the blower on high.
I do this and have never had AC smell issues on all of my vehicles including my F150..
This will tend to evaporate any condensed water lingering in the HVAC system.
Bacteria love to wallow and procreate in damp dark conditions.

How do I check the AC water drain?

Try changing your cabin filter. Helped with mine.

Try one of these. I'm running the FRAM one currently and it helped get rid of odor from previous dog-owner of truck....



I may try one of these when time to change again...




And I stash a couple of these in the truck also...

Try an Ozone machine, run recirculating a/c and let it air out afterwards so you don't die from the ozone.

BG makes a product called Frigi-Fresh and it works well. I recommend giving it a try and then doing what others have mentioned to dry out the HVAC box (mostly the evaporator) before shutting the truck down.

I find keeping my shoes on helps...A little :)