Okay Dude relax.
1] Your air suspension doses not work the way You are think[check your owners manual
2] the system works like this .............
The high setting is[OFF ROAD] as in if You need to be off road the X5 will maintain this height up to 30 mph and will go back to the normal [middle setting].
the low setting is for unloading or working on the car. it will re-set to the middle setting on it own as You drive up to 30mph.
So the middle setting is the NORMAL setting at any speed .You can not adjust the ride height above 30 mph.

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2006 4.8IS
65K MILES
PURCHASED 7/13