My car was flooding the passenger floorboard every time I ran the A/C so I did all the usual suggestions, but nothing worked. I decided to rip out the dash and fix it once and for all. There is virtually no information on the internet about how to do this, so I'm sharing what I learned to help anyone else considering this. My car is a 2002 GTP. Plan on spending a full day each for teardown and reassembly.
The reason my car was leaking was because there was no rubber elbow on the drain tube. Water would run back along the outside of the tube and through the foam gasket that surrounds it at the firewall. It's a stupid simple fix, but I had no way to know that without completely taking it apart.
Every component of the dashboard must carefully be taken apart and pulled out. None of the bolts or screws required special tools other than a couple Torx bits. Some of them are hard to get to, but not impossible with an ordinary wrench and some flexibility. The hardest part for me was getting some of the wiring harness clips to release. The steering column must be unbolted from the support brackets, but does not have to be removed. The instructions I followed said to remove the brake pedal, but I don't think that's necessary.
In order to put the HVAC module back together you will need a seal kit, part number 52478813. Not a single place I checked normally stocks it, so expect at least a week before getting your hands on it. The list price is $137.37. A few websites sell it cheaper, but after shipping and uncertain delivery dates it seems worth it to me to just get it at the dealer. They can most likely get it sooner.
I have all the instructions required to do the entire procedure, but I had to pay for them so I would prefer not to publicly post them. If you are doing this and would like a copy, just send me a PM and I will email them to you. My car won't be done for another week or so, so feel free to ask any questions. I can take pictures on request of specific parts or areas.
