[Sportstick]

To rule out one potential issue, you do run the HVAC system on AUTO rather than try to use it manually? The AUTO function includes a self-drying feature which prevents the growth of smelly mold. Once the problem starts, however, a trip to the dealer for ductwork cleaning is usually required to resolve. Over on the MB forum, from where I came last year, all who had this complaint about HVAC smell were those who tried to use their HVAC manually. There were no complaints from those who set it to AUTO and let it manage itself.