my 1986 monte carlo only blows air on floor on drivers side. & just a little on on 1990 Chevrolet Suburban 1500

wher is the flap actuator located ? can it be repaired or need to b replaced i don't know what it looks like

it is vacuum activated by the control head. it is under the left side of the dash by the gas pedal. it moves for all 3 positions but needs to be checked by someone who knwos the system.

thank u very much. larry