My heater only blows cool air

There is a recall on this problem most likely what has happened is you heater adjustment door inside the hvac unit is broken and needs to be replaced it breaks where it goes through the wall of the unit into the actuator that turns it because it was made from plastic after a while it just snaps off. I would definetly have the dealer fix this because its 9 hours of labor and about $1300.00 and it was just recently recalled so they will fix it.