Oldsmobile Silhouette Owner's Manual page 207

To maintain a comfortable temperature in the rear, use
either rear fan control to adjust the force of air coming
through the rear outlets.
Select the desired climate control mode using the
directional controls on the instrument panel (see "Mode
Knob" earlier in the section). The mode you choose will
regulate both the front and rear climate control systems.
Rear Air Vents
To maximize airflow through the rear heater outlet,
place the left bucket seat in the second row in the
forward position (see "Adjusting Rear Seats" in
the Index).
The vent behind the left rear seat is the cold air return
vent. Be sure to keep it free of obstructions.
Keep the area around the base of the center instrument
panel console and between and under the front seats free
of objects that could obstruct airflow to the rear.
yellowblue
3-7