Floor Mode
WARNING: This page is about a different car, the 2002 Oldsmobile Intrigue. However, it is still accessible from the selected car via links, so may be relevant.
When the operator selects FLOOR, the A/C Bi-level mode actuator has vacuum applied to it through the Brown vacuum line, pushing the vent door closed. The heater/defroster actuator has vacuum applied to it through the Red vacuum line, pulling the defrost door closed and opening the heater door through mechanical linkage.