my 2004 has an occasional musty,mildew smell coming from the heater/ac unit.it does not do it all the time,therefore the dealer can never locate it.of course,now that it is out of warranty,it does it more often.has anyone else run into this?

 

Check the drain for the HVAC box, this is usually the source of the smell - condensation accumulating and getting moldy. You can clear it out from the engine compartment side of the firewall.