heater controls will not change from defrost to floor, vent,etc. on 2003 Lincoln Navigator

replaced the control module with no change in condition. The light indicator show it has been switch, but the air still comes out of the defroster. Not very effective for air conditioning. Are we looking at the main computer under the hood or is there a motor that has malfunction and where would it be and how difficult is it to get to?

Asked by for the 2003 Lincoln Navigator