hi just wondering if anyone can point me in the right direction with this. my father in law has a 93 corsica and whenever it rain he gets a swimming pool in the passenger side footwell. my only guess is that its rainwater running down the windshield and making its way into the cabin through the hvac system, but how do i stop this?

is there any kind of drain at the firewall that could be clogged or is the flooding caused by some kind of seal around the wiperblades etc?

We just started getting the same thing when it rains. Normally the problem is that water collects behind the wheel well until it rusts and creates a hole but I checked this out and that was not the case.

I am thinking perhaps its the lower seal of the window.