Passenger side under the firewall area there should be a little rubber hose sticking out. Also if you peal back the carpet you should see it. It's around where the passengers left foot would be. I made the mistake of knocking it loose one day and it kept draining into the car. We couldn't figure out where the leak was coming from especially when it hasn't rained in a while.:headbang:
Why do you think it's plugged up?