Cabin Air Filter
 

My C300 is only 20 months old. There is mould smell when we start the AC. This lasts for about a minute or so, then it is gone. Wonder why this in an almost new car. Where would the cabin air filter be?? Any one on this. Please. I looked under the hood. There is a black box onthe left hand rear end above the battery, is that where the filter could be?