insufficient airflow from vents

my 99 explorer sport with 96k ,purchased at 72k,has never had adeqet airflow from the front vents,the rear courtesy vent for rear passengers blasts,but the fronts on setting 3 have the flow as if setting 1,asked dealer if vehicle has filters and they say no on this vehicle.any suggestions would be appreciated!

your talking about the a/c right?

so the rear passenger blasts cold?

yet barely any cold air blows from the front vents? or does the front vents blow warmer than the back?

what Im getting at here is that if your vents arent opening fully I might be a loose vacuum line or disconnected vacumm line.

or it might be a problem with your a/c ,....but theres not enough information to tell whats wrong with your a/c if anything.......it might be something as simple as servicing your refrigerant.

it doesnt matter,ac or heat,its the actual airflow/output from the vents that im concerned about.