Musty Smell from A/C vent


New member
GMC Terrain - 2013
Musty smell comes from the A/C vent under random conditions and any setting. A/C works fine and a typical outing might be to several locations on a shopping day. A/C can be off, recirculating or using outside air. No problem for a couple of stops. On the third drive at some random point the smell comes on so strong you have to open the windows. After five minutes or so, the smell disappears.
Dealer has upgraded the firmware for the fan blower to remain on after turn-off. Air filter has been checked (looked fine) and replaced multiple times. Mechanic has verified the drain is completely open. Also, poked around with a visual snake seeing nothing wrong. Several sessions of Frabrize-like disinfectant only covered up the smell but never solved the problem. This has now been going on for over a year. I've seen multiple posts but don't ever seem to see a corrective answer.


New member
I have gotten in the habit when heading home to shut off my A/C about 1/2 mile from my place, but leaving the outside air on to dry out ther air vents etc..

This is an issue for Chevy HHR as well. Although I have managed to avoid it in mine for over 10 years.

I was told you can get an ozone generator to put inside your vehicle & it is supposed to kill off the mildew etc.