I have an 03 Impala which now leaks into the passenger floor when it is raining. Bad! Thinking it was the lower part of the windshield I duck taped the seam but no change. Also, it doesn't leak when the car is parked and it is raining, just when I am driving, so water is coming up into the inside somehow. Now what is weird about that is that it drips off of the interior light down where your feet would go, and not coming up through the floor. Any suggestions? Thanks

 

Possibly your heater core... But if it's only when your driving when its raining, prolly not. I fought a problem similar to this, for 6 months, on my wifes 03 Eclipse. I ended up having to pull the carpet out, wait til it rained and drive it, still couldn't find a leak. So I just siliconed every crease in the floorboard.
Could be coming in from one of the weather seals on the door to.

 

If this pertains to anybody, I found it... I found a small hole in the wheel well. There is a seam that is covered up by some sort of thick black caulk. A part of it came loose and there was a hole leading into the cabin in front of the foot board. I caulked it up and that took care of it.

 

Awesome. thanks for getting back to us. Thats pretty much what happened to our Eclipse.