FORD 2003 Expedition v.2 - Manual (Page 214)

When exiting the vehicle, the air suspension will automatically lower the
vehicle to its lowest height to provide easier exit. You may hear a buzz or
click from the air suspension system when the ignition is turned off. The
air suspension system will stay active for 40 minutes after the ignition is
turned off to accommodate any load changes. (The air compressor may
run when the vehicle is off; this is normal.)
On vehicles equipped with air suspension, turn the air
suspension and the ignition switch off prior to jacking, hoisting
or towing your vehicle.
The air suspension shut-off switch is located behind two access panels
on the left rear quarter trim panel, near the liftgate. Press the tab down
to unlock the second access panel.
Driving
214