The passenger floor board fills with water when it rains heavily.
Hello, there are many entry points for water into the cabin. Assuming all windows, doors and possible sunroof were closed, the following is what I suggest. If your vehicle is equipped with a sunroof, start there and run a garden hose over the sunroof for a while and see if there is water entering and dripping possibly from the headliner area or down by where your feet go. There are drain hoses for the sunroof that run from the sunroof to the floor and usually exit the vehicle. It is possible for the sunroof drain hose to become clogged and the water to drain incorrectly, for example over flowing onto the headliner dripping onto the floor. It is also possible for the water to run down the backside of the panels to the carpet. Separately, the heater box also has drains that can get clogged and need to be cleared. There has been a TSB 0033-14 for this issue for insect intrusion. Simply accessing the hose and disconnecting the hose from the box to see if there is water still in the hose would be a good indication. While the hose is disconnected it allows an opportunity to clear the hose out with a thin wire or the like. Lastly, water might be coming in from a door seal or the windshield which would be found while testing the sunroof. You may need the aid of a mechanic to remove panels and help find the leak since it will usually take two people to find the leak. One to work the hose and the other to look inside the car.
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