Dmul98

Recently I have noticed a musty smell from my vents when using ac. It seems to clear after 20 - 30 minutes but returns at next start up if car sits for a bit. Any help appreciated.

GMJim

Change the cabin air filter with a charcoal style. The activated charcoal will absorb the odor.

Rocketmanwpb

Your condenser drain may be clogged causing mold and mildew to form in the fan housing. Need to go under the car and blow out the drain with some air.

You can also spray some something like Neutra Air through the cowling vent while the AC is running.

Gearhead Jim

The above posts may be helpful, but...
A dealership can activate the "afterblow" setting in the car (BCM?), it will run the AC fan for a while after the car shuts down, in certain conditions. Developed especially to cure this problem.

hawkgfr

Run your air conditioner without the little gold light on the air button. When its on the air is in recirculation and doesn't not let fresh air in. Rapid temperature change, cold to hot causes condensation in the duct work and the moldy smell. (after you cut the car off and leave it overnight etc..) In the other mode the door that lets fresh air in is open and thus doesn't allow the condensation to form as easily so there is less moisture and what is there can dry more quickly.


In manual mode anytime you turn the air on and there is a 10 degree difference between outside and inside that little gold light comes on automatically. You have to manually turn that light off. You can wait until you are good and cool if you like. When you press it after its been on a while you can smell the fresh air coming in the car...


I've never had the smell in any vehicle. You won't either if you don't run in max all the time.(recirculate) IMO.

DillingerRadio

This condition may be caused by condensate build-up on the evaporator core, which does not evaporate by itself in high humidity conditions. The odor may be the result of microbial growth on the evaporator core. When the blower motor fan is turned on, the microbial growth may release an unpleasant musty odor into the passenger compartment.

There are several other possible sources of a musty odor in a vehicle. A common source is a water leak into the interior of the vehicle or foreign material in the HVAC air distribution system. This issue is documented in service bulletin 99-01-39-004C.

V8lust

A simple replacement of the normal cabin air filter worked for me, still no problem two years later.

Seadawg

This is almost done to every AC vehicle in the humid southern areas now. Very easy and fast for the dealer to do.