02 wet floor

Hello. When I tore apart my 02 4wd ex-cab I found the passenger side floor insulation was wet and it had started to rust the floor only in the corner where the cab mount is. There was no sign of where the water was coming in. Also no through holes in the rust anywhere. There wasn't a puddle, just wet insulation. We poured a 5 gal bucket of water into the fresh air vent very fast and then there were some drips into the cab but they were on top of the carpet. I have never noticed the carpet to be wet. And that was a huge amount of water all at once which really isn't what happens to the truck. I saw in the "Mystery Leak" thread that @fxntime brought to light that maybe the ac condenser drain could be related to my problem. Where would I look for that drain hole? Or, does anybody have any other suggestions? The cab is off the truck and the full interior is out but not the dash. I'm open to suggestions.
Thanks
John

 

Drain is in the passenger wheelwell/engine area right by the frame. Comes out of the blower box bottom, about a 1/4 black hose/line a couple of inches long. It can drip into your frame and cause rusting so many people lengthen it to get it past the frame opening. Daubers like to lay their eggs in it and seal it up.

 

This is my 98. Same spot for 01-04s

looking down on the passenger side firewall in the engine bay.

 

@fxntime & @Madjik_Man Thank you very much gentleman. Another lesson learned.