2001 Sebring LXI a.c. vent problem

Hello there every1!!! Im currently driving a 2001 Sebring LXI sedan 2.7 v-6. Problem is, the ac vents dont work. The air blows cold, but it only blows out of the defrost vent and occasionally at highway speeds, will blow for a second or two out of the dash vents. Ive already replaced the ac/heater control, but that did nothing.. No matter what setting it is on, it only blow out of the defrost vent by the windshield. Any suggestions??? thanks