Why does the Cabin air smells moldy or musty coming from the vents?

Hello, Check and replace the cabin air filter if needed, and ensure that the air conditioner evaporator core drain is allowing water to exit the HVAC central housing. A good way to see if water drains is to run the air conditioner with the vehicle parked for about 20 minutes. You should get a spot of water on the ground up front. If everything is in order, you may have a little mold growth, and there are commercially available products for just this issue.