condenser water inside but drain not plugged

My 95 Lumina APV leaks AC condenser water into the interior and has soaked the front floorboards and insulation beneath the carpet. I'd like advice on sealing the leak.

I've traced the source of the leak to the lower, right corner of the condenser airbox where the plastic box seals to the metal cowling with black foam. The external drain plug on the engine-side of the condenser is not obstructed- water does drain out and I can push a round brush into the fitting but the interior leak is lower than the drain plug. (The external drain is about 1/2" above the bottom of the box).

I've removed the seats, peeled back the carpet and removed the lower dash panels and center console. I've removed the cover from the condenser box but it looks like I'd have to remove the entire dash and instrument cluster to get full access to the condenser. How do you gain access to this area? I've taken some small digital pics of the external drain and the internal leak area if anyone wants to take a crack at this. Thanks in advance, Brian.

I never got any replies to my question so I'll post what I did in case anyone has the same problem. I couldn't get to the foam rubber seal that was the source of the leak so I jacked the van up and drilled a 1/4" drain hole in the bottom of the metal portion of the condenser box. This is the stamped, black metal pan that is sealed to the firewall. I used an air drill that's fairly narrow and a 8" long drill bit to reach the box from beneath the van. From the interior, I ran three beads of silicon caulk, one on top of the other, until I made a wall around the new drain hole. I masking-taped a 4" piece of a drinking straw to the caulk nozzle so I could reach into the condenser pan. Whatever water leaks out of the condenser box is trapped in the metal cowl and drains out the new hole. I replaced the wet carpet padding with new pad from a local uhpolstery shop for $12. Done. Hope this helps someone else.