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.

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