2005 Chevy Equinox severe musty odor / both parked & dr

MY 2005 CHEV. EQUINOX HAS DEVELOPED A SEVERE MUSTY ODOR SUDDENLY. THE INTERIOR HAS BEEN CLEANED. NO SIGNS OF WETNESS.I
REPLACED THE CABIN AIR FILTER AND SAW NO SIGNS OF WETNESS. NO WATER LAYING UNDER COWL. CAN WATER BUILD UP IN AIR CONDITIONING
BE CAUSUNG THIS ODOR? WHERE IS THE DRAIN LOCATED? THE SMELL IS SEVERE EVEN WITHOUT DRIVING THE CAR.

THANK YOU
DONALD WILBANKS
[email protected]

ps: I SUBMITTED QUESTION 3-29-08 BUT YOU SAID
YOU RECEIVED MY DONATION BUT NOT MY
QUESTION.