Is the condensation drain tube plumbed outside the car? Sometimes, boxes get R&Red and the line gets stuck inside the car. If so, condensation will run into your car instead of outside.

 

 

Well, you can look in the engine bay to see if anything is attached and if it looks like water has been coming out.
but....
It's probably behind the air box assy.

 

 

I'll take a look, but I could swear it's a rubber hose that comes through the firewall..
but it's been a while since since I've had to deal with it.

 

 

The drain is rubber usually with a duck bill end on it and comes through the firewall towards the center of the car behind and slightly above the subframe. Even if connected correctly it could be plugged. Dirt over time gets in there. I once owned a Pontiac with a plugged A/C drain and crawled under without raising the car - I was slimmer then - lol. Nearly pinned under the car I stuck the wire I had with me up the drain and got a quart of very nasty water in the face.

 

funny, not funny. And really gross.
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The inlet/outlet of the heater cores are known to crack. I assume ours are the same. If someone wasn't careful R&Ring the hoses, they could have broken one.

 

It should be very easy to discern whether it is coolant (a leak) or water (condensation).

You said you found the external drian and it was OK, did you check it for blockages?

 

Me trying to wiggle out and going nowhere would have made a great youtube.