Whilst looking for an answer to a some information I wanted I came across this pair of videos.
I found out what I wanted from these videos, but as I drive an Actros (amongst other tractor units) I was concerned that the driver appeared to be driving around with diff lock engaged! Certainly I checked on the unit I drive today and the diff lock symbol only comes on when I select diff lock.
Perhaps other Actros drivers could comment?
I thought the orange sign in the dash with the wheels on ment the middle axle is up.
The display will show lift axle or diff lock - the relevant bits of the symbol are animated/highlighted to show what.
That explains it, the units I drive only have one rear axle.
Héraultais:
That explains it, the units I drive only have one rear axle.
Get a proper unit 
NewLad:
Héraultais:
That explains it, the units I drive only have one rear axle.Get a proper unit
LOL, very few units in France with twin rear axles 
Héraultais:
NewLad:
Héraultais:
That explains it, the units I drive only have one rear axle.Get a proper unit
LOL, very few units in France with twin rear axles
I was just pulling your leg, all my comments regarding the amount of axles you truck or ‘van’ as some would say, has are purely in jest at some of the Super Drivers who only drive artics and wouldn’t be seen in a puddle jumper!