Bi-Level Mode
WARNING: This page is about a different car, the 2002 Pontiac Firebird and 2002 Chevrolet Camaro. However, it is still accessible from the selected car via links, so may be relevant.
When Bi-Level is selected, air is delivered through the instrument panel outlets and to the floor outlets. Vacuum is applied to the mode actuator through the Violet and the Green vacuum lines, and to the defrost actuator through the Yellow vacuum line. Applying vacuum to both sides of the mode actuator will hold the vent door stationary in the half open position. The defroster actuator will retract, closing the defroster door and open the heater door through mechanical linkage.