DC -
Does your car drip water from underneath, about where the dashboard would be, after using your A/C, and shutting the car off ?
If not, then that little rubber tube that is supposed to drain all the moisture out is clogged..
I quickly did a little research via google, and I think on Toyota Vans, the little tube might be on the Passenger Side of the Firewall, and I assume towards the bottom of the firewall, as you need to have the tube lower than the Evaporator, so the water will flow down and out..
There are Toyota Forums that talk about this also..
See if you can ask the Toyota people to tell you where it is, or better still have them verify you have this and put it on a lift, find it and run a wire through it to unplug it..
All Air Conditioners get moisture on the evaporator , and the moisture has to go somewhere as its collected..
This is why A/C units smell because the little evaporator (looks like a little radiator), behind the Dashboard, usually at the bottom, behind a console, etc., is swimming in moisture that needs to go out the little tube and onto the ground underneath the car..
Hope you can get this fixed !
Dan F