My 2020 F250 has started producing a bad musty smell when the A/C first turns on. The smell clears in a minute or two, but I was wondering if there is some filter or condensate trap that I should be cleaning to prevent the issue?

 

There is a cabin filter that you should change regularly.
But, musty smells are often from mold and mildew that happens when condensation is trapped in the bottom of the hvac housing due to a blocked drain.

 

There is a foam that can fix that google it

 

I found that running the AC in non-interior recirculate mode a few minutes prior to turning off the vehicle prevents it.

 

The AC drain needs the elbow installed. There is a TSB to address this.

 

When you get close to home turn off the AC and just let the fan run.

 

I second the cabin air filter, had the exact same problem on my 2017. I changed the filter and it took care of the problem. It’s a cheap fix to at least try first.

 

Cabin filter. I have a detail business and when the client wants a smell from the vents to be eliminated or reduced I ask if the cabin filter has been changed lately. If not or even so, I will take it out at very least and vacuum it then treat the filter with one of our fragrant deodorizers for assistance.

 

I have a similar issue, smells like vinegar when I first start the truck and then it goes away after a minute or two. changed the cabin filter and that did not fix the problem.

2020 F250 Platinum

 

Got in my truck today and you’re right. Pure vinegar smell upon ac startup. Quickly clears but wow is it pungent. Anybody had any success?

 

Post #5 is your fix. The problem is while driving especially in high humidity the condensate water is pushing backwards through the firewall opening and draining to the carpet below.

 

I live in the deep south with very high humidity, right now it is 99%. Mold and mildew are common problems. In addition to changing your cabin air filter, get some AC evaporator & duct cleaner. Napa part #s 409523 or 801601, (same product different pkg). Follow the directions on the can. The stuff works. You did not mention wet carpet so drain issue may not be your problem. would install elbow anyway.

 

Ill throw this out there as a long shot. Might be your batteries gasing out. Fords had a problem with bad batteries for the last couple years, Im on my 3rd set under warranty on my 19. When they start going bad they stink real bad with the ac on. Probably not your problem but worth looking into.

 

I actually asked Ford to check my batteries for this reason and they indicated they were fine. Doesn't mean that they are not causing the problem though.

 

I purchased my 2016 half ton from an area that rains a bunch. I live in the desert. Whenever I would start the AC, I would get a musty smell. I don’t recall a vinegar smell but musty for sure. I took a spray can of Lysol disinfectant, turned on my truck with the AC blasting with recirc turned off. Sprayed half the can (took a while) into the exterior vents below the windshield. The next day I did it again with the rest of the can. This completely solved the problem for me. There was a pretty potent Lysol smell for a day or two but that faded away and the bad smell never returned. I think it does help that I live in the desert and I’m not adding or continuing the issue, but it fixed the original issue for sure.