Point of order for those with full air suspension
 

If you have your trailer hooked up behind, and 13 pin trailer plug is connected,
your X5 will no longer go up and down.
Enters a special "trailer mode".
Comes up on MID when hi/lo selected.
Found this out while on holiday recently,
came across roadworks,
pile of gravel on road,
says to myself no problem here,
hit button up,
and a big fat nothing.
Thought air suspension was playing up again.
Funnily enough, trailer mode did not come up on the MID
first few times I tried it.

End.