2004 Open Road Trailer 2004 Impala Blowing Air Constantly?

2004 impala blowing air constantly? - 2004 open road trailer

Who has this problem? When driving on the road, the air through the vents when I have the fan. When I open the windows of all, increases the speed of the air in the cabin. I think this is a problem of the doors and is also the cause of odor in the cockpit. Any help?