I own a 2002 Toyota Avalon with 123,000 miles. Recently I have noticed that the floor board on the passenger side is wet. It appears to be wet only on the bottom and not along the edges. My first thought was the heater core but I do not appear to be loosing any coolant the car has not overheated and the tempature is normal. Also it does not appear to be leaking under the dash. I have also checked around the passenger door during a rain storm but do not see any visible leaks. Does anyone have any suggestions on what may be causing it? Thanks !