Musty Smell from AC
A musty odor when the AC is on typically indicates mold or mildew growth in the evaporator case or cabin air filter due to moisture buildup.
Diagnosis Details
Possible Causes
Clogged or dirty cabin air filter
Mold or mildew on the evaporator coil
Blocked evaporator drain tube causing standing water
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What You Should Do
Replace the cabin air filter first.
If odor persists, use an AC evaporator cleaner spray (foam) and ensure the evaporator drain is clear.
Run the fan on high with heat for 10 minutes after cleaning to dry the system.
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Disclaimer: This AI-generated diagnosis is for informational reference only. Always consult a qualified mechanic for an in-person inspection. AutOwner is not responsible for decisions made based on this information.
