68Hodaka

My 99 Ranger has a strange problem.
The faster I drive, the more air is being pushed out of the floor vent.
This is happening with both Fan and other selector switch to "OFF".
(By vent, I mean the vent where the lower heat comes from).

Even more strange, if I roll either window down, a LOT more air comes out the the floor vent.
Note: Air from the window is not getting all the way to the floor.

I'm lost. Even if the vent isn't closing all the way and allowing air to come in,
why on earth would more air come through the vent with a window open?

Any ideas what might be happening here?

Your help is certainly appreciated.

360ci

Sounds like a loose blend door. Not an easy fix even for a DIY person as it will require taking apart the majority of the dash to get to the HVAC box that houses the blend door.

When you open your window this takes away any back pressure to the air coming in through the vent and allowing more of a breeze to pass through the cabin. Obviously the faster you drive the more air will pass through with the window open. This is one of the many reasons airliners use pressurized cabins; besides having enough O2 for one to breath above 10,000ft ASL.

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'00 Durango R/T 360ci 290hp (modded); 138,500m
'06 Pontiac G6 GT 3.5L 220hp; 44,000m
'12 Chrysler 200 Limited 3.6L 283hp; 13,000m
'99 Taurus 3.0L 2V Vulcan 145hp; 154,300m - Traded
Amsoil in all vehicles!