I don't think the vent is completely blocked, but it may let a smaller amount of air out than I'm used to. Most cars have an inlet vent with a HEPA filter (or at least some sort of filter), usually located somewhere below the dash. Could the Ridgeline be relying on that?All vehicles have vents which allows the pressure to "escape" when closing the doors. In the Taco its behind the rear seats, also where most of the road noise comes in. I wonder where the RL hides these vents? Unlikely that it's behind the rear seats as there is no gap between the bed and the cab. I wonder if the flaps in your vents, where ever they are, are perhaps stuck.