Bi-Level Mode
WARNING: This page is about a different car, the 2002 Buick Regal and 2002 Buick Century. However, it is still accessible from the selected car via links, so may be relevant.
When the driver selects the BI-LEVEL mode, the MODE switch is adjusted until MID and FLOOR are displayed. In this mode, air is delivered through the instrument panel and floor outlets. The HVAC control module grounds the lower mode valve solenoid control circuit. When the solenoid is grounded, vacuum is applied to the mode actuator through the Brown and the Blue vacuum lines, and to the defrost actuator through the Red 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.