A dirty cabin air filter can become a source of bad odors by trapping moisture and outside contaminants that promote bacterial growth.
Musty odors from the A/C evaporator are a common issue in humid climates and may require spraying a biocide or air fresher into the HVAC housing to get rid of the smell. But that won’t help if the odor is coming from a filthy, soiled cabin air filter.
This video is sponsored by the Automotive Distribution Network.