If i remember correctly the cowel drains are under the cowel cover near each fender. The one that usually causes moisture to get into the car is the one on the passenger side aswhen the water backs up and can't drain it overflows into an opening for cabin filter (under the glove compartment). The drain holes are small and leaves or pine tags will clog them easily. My bro-in-law had this issue and when i checked mine there was only minimal leves that needed to be removed...hope this helps. PJ