A/C leaking inder dash?

My wife complained that liquid was dripping on her from under the dash. I thought heater core, but she said it was cold. I felt up under the dash, and felt a wetness.

Come to find out, she had the A/C on the the vent/floor setting. I am assuming it is the condensation building around the duct (it was plastic duct tube that was wet when I felt up underneath). I know it was not a heater core because it would be hot, and leaking under the passenger side. This was leaking under the driver's side. I also think it was condensation because it was night time.

Has anyone ever had this happen? I am not sure if it would be the same since my truck has the steering wheel on the right side (I am living on a humid island of Japan). I assume it is, but just backwards. Also, since there is a lot of humidity, it would be just condensation. Any opinions?

There is a drain tube for the condensation, goes thru the floor/firewall and dumps the water under the vehicle. These tubes frequently block up and the result is what you have. Find and unclog the tube.

Blow air up through the tube from underneath the truck.