Technical Bulletin (HVAC, Unpleasant Odor):
Condensation, which is a normal condition in all A/C systems, can cause a musty odor. If the odor is noticeable in the vehicle when the engine is not turned on, the cause may be mold and mildew in the passenger compartment, and not be related to the A/C system. All other possible sources of the odor must be investigated before this document can be performed. This document contains the procedure for the VW method to remove musty odors