1999 Other Jeep Models why

Need to be more specific on what you are driving please. On older wrangler type vehicles the air comes out of the center of the dash and just kinda splits to both sides. On older cherokee's the heat is also split but on the passenger side it goes thru a horn that directs this heat to the floorboard above the feet and to the center of the vehicle some. This extra piece just pushes in place and it is prone to getting kicked off and after time lost or just thrown out. Hope this helps if not let me know exactly what type jeep you have. Thanks Curt