Mode Control Lever (Optional System) S" Blazer & Pickup Models)

When this lever is in the "VENT" position, all discharge air is directed to the upper outlets. The "DEF" position directs most of the air to the windshield (defroster) outlets with some directed to the floor (heater) outlets. When in "HEATER" position, most of the air is delivered through the floor outlets with some air flow to the windshield outlets.