Water leaking floor boards passenger side

Water seems to come in when air-conditioner/vent is on; also now when heater is on. It’s just plain water, no smell to it. Ran a hose in cowl area and windshield but no leak; drains are not plugged. No loss of fluid from radiator.

Thanks for anyone’s help.


Try shining a flashlight under the dash while running water through the cowl. The light reflects off any water leaking through. This is how I found a leak between the inner fender and the firewall on a 2000 Blazer.

Ed B.

It’s just a plugged AC condensate drain.

Time to clean out the A/C condensation drain. Just like a de-humidifier your car’s A/C removes moisture from the air (the A/C runs when you have defrost on, even if the A/C is off.)

Under the car about where the passenger’s feet go, is usually a small black hose. This is the drain. It may be cleared by CAREFUL use of a little compressed air or string trimmer line to clear the blockage.

I say careful because if you get too enthusiastic you can pop the hose off the other end (hard to get to) or damage the hose. Most any shop (stay away from the chains) can handle this quickly and cheaply.

Agreed, your problem is simply a clogged AC drain. This is a common occurrence.