Bi-Level Mode
WARNING: This page is about a different car, the 2002 Cadillac Eldorado. 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 Red and the Yellow vacuum lines, and to the defrost actuator through the Blue vacuum line. Applying vacuum to both sides of the mode actuator will hold the mode door stationary in the half open position. The defroster actuator will retract, closing the defroster door and opening the vent door.