Started parking on an incline, nose uphill. Noticed that my windows would fog up in the interior when car warmed in the sun. Checked the floor mats. Both sides drenched every time it rained. Finally decided to check it out after a night of rain that drenched the interior. I backed car down to the hose. No water come in when I hosed windshield and hood down. Eventually took windshield arms off and removed plastic housing along windshield base. Check rain channels with both compressor and water hose - all clear. Determined the only cause could be the heater intake hole in the fire wall - foam gasket was soaked on bottom. Perhaps with the incline, water is backing up enough to enter vent in heavy rain. I took some water proof duct tape and raised the bottom of the opening about 1-1.5 inches. Fan seems to work fine.