On a recent trip home I had to use the dash defrost to remove some minor condensation from the windshield. Not the type of moisture that happens when there is a buildup in the coach, just your typical cool weather windshield variety. Anyway, when we turned it on there was an immediate musty smell from the vents. This happened periodically throughout the day. Our new coach only has 7k miles on it and we've had it less than a year but I guess somehow some moisture got down in the vents. Is there a cabin filter or anything I can check/replace? Is there anyway to remedy this?

Plugged drain tube is my first guess. That seems to be the vast majority of the cases anyhow.

Mine does that if it sits for awhile. I was told to turn off a/c a few blocks from home to let moisture escape. (don't know if this really works but...) I then used a product called FrigeFresh made by BG. I got mine at the Toyota parts counter. Sprayed that thru the outside intake with the unit running and the smell has not returned.

A lot of people keep the AC on until they are at home or at there intended destination. This practice will lead to moisture being trapped in the vents. A safer practice is turning the AC off about one or two miles from stopping. This allows the system to dry out, thus cutting down on trapped moisture in the vents. Leave the fan on high, but cut off the AC.

I've never used my dash air. I only used the heat and defrost to get rid of some moisture or to warm up my feet.

The "dash air" is a system, a single unit with both heat and cool capabilities.Defrost does run the A/C compressor to dry the air.You should use the system more, more is always better.Find and ensure the drain is clear. Easiest way to find it would be to run the dash A/C until the water starts dripping out.As was stated they do have various chemicals you can squirt into the intake to kill and mold or other smeely stuff that might collect in the system.

Musty smell from dash vents | Good Sam Community

mogman
Explorer
Apr 23, 2014
You may end up having to evacuate the A/C system and remove the evaporator unit and wash and scrub the housings and evaporator with detergent, dry and re-assemble and recharge.
I worked for Honda for many years and the musty smell was a common problem...cleaned and washed many evaporators.

Also, as stated, locate the evaporator case drain hose and make sure it is clear. If there is no cabin filter on your vehicle, lots of debris, pine needles, small leaves etc. accumulate in the casing and hold moisture leading to the smell.
Effy
Explorer II
Apr 23, 2014
jolooote wrote:
hmmm ...maybe a dead critter has laid to rest in an air duct?

No. It's a damp smell. Not dead critter.
jolooote
Explorer
Apr 23, 2014
hmmm ...maybe a dead critter has laid to rest in an air duct?
bob213
Explorer
Apr 22, 2014
Effy wrote:
bob213 wrote:
Mine does that if it sits for awhile. I was told to turn off a/c a few blocks from home to let moisture escape. (don't know if this really works but...) I then used a product called FrigeFresh made by BG. I got mine at the Toyota parts counter. Sprayed that thru the outside intake with the unit running and the smell has not returned.

Where is the outside intake? Same as the air cleaner for the engine? Sorry if it's a dumb question, I have had vehicles with a cabin air filter.

Mine is in the engine compartment on the firewall.
No the engine intake....
Effy
Explorer II
Apr 22, 2014
crasster wrote:
Did it happen periodically when you turned it on and off? Or did you just leave it running and then suddenly you smelled it?

Well, when I smelled it initially when I turned it on, then it dissipated after a minute or so. But if I turned it off, then a while later back on, I smelled it again. Again it dissipates after a few minutes. I will say that I noticed it after about 24 hours of hard rain and a lot of it we drove in. Wonder if moisture is getting into the system, but like I said I am not sure where the intake is. Under the hood, same as the airbox for the engine or is there a dedicated filter/intake for the dash AC?
OhhWell
Explorer
Apr 22, 2014
Pauljdav wrote:
Use Lysol. spray the lysol into the air intake when you have the system running on full blast.

This is the cheapest and easiest way to fix this.

Paul

I have had that work very well in a used car and even a fridge in the past.
Pauljdav
Explorer
Apr 22, 2014
Use Lysol. spray the lysol into the air intake when you have the system running on full blast.

This is the cheapest and easiest way to fix this.

Paul
crasster
Explorer II
Apr 22, 2014
Did it happen periodically when you turned it on and off? Or did you just leave it running and then suddenly you smelled it?
jolooote
Explorer
Apr 22, 2014
Check under the hood to see if there is a 'Dip' in the hosing. It'll collect water in the bottom there. If so, lift the dip area and strap it up higher.
down_home
Explorer II
Apr 21, 2014
Dealers have an probably auto parts stores a spray foam, to spray down the outside cowl vent, to kill and clean mold,pollen and other stuff out. I think it turn to liquid and drains out the drain hole/line.
Ask the Mh mfg about using it perhaps.
I had to have it done twice on some auto I had back whenever.