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 !

Its' either a clogged A/C drain line that's making collected condensation drip on the floor, a leaking heater core, or a leaking windshield seal. Easy for me to say but, you have to look a little closer. One clue, if the liquid is slimmy, it's coolant from the heater core. If not, you'll have to chase down the other two possibilities. Try drapping plastic in the area to catch the leak, then inspect the fluid.

Thanks for responding. The liquid does not appear to be slimmy so I will look closely at the other options. The A/C has not been ran for several months. Would enough condensation still form to saturate the floor board? Any tips on locating the drain line and clearing it?? Again Thanks for taking the time to respond!

Its' either a clogged A/C drain line that's making collected condensation drip on the floor, a leaking heater core, or a leaking windshield seal. Easy for me to say but, you have to look a little closer. One clue, if the liquid is slimmy, it's coolant from the heater core. If not, you'll have to chase down the other two possibilities. Try drapping plastic in the area to catch the leak, then inspect the fluid.

The A/C is always on if you use the AUTO feature, so still could be the problem. Another possibility is your sunroof. There should be drain holes in the gutter of the sunroof (there are on a couple other toyota's I have, but I've not looked at my Avalon). If those holes get clogged up with debris, water can build up in the gutter and leak into the car. Alternatively, the drain-hole hoses (which run in the A-pillar) could have come loose or developed a lead, leading to water in the car.