In the other 4x4s we have the central diff lock is manually selectable, along with the ratios.

In the full fat however it is all automatic, i cycle the low/high ratios quite often, but obvoiously cant engage the diffs.

Is there any way to make them engage ? Is it necessary to give them a bit of use now and then to prevent seizure?

I remember on our colorado a few years back the lever completely jammed in high and unlocked, dont want them to jam on the ff.

Also i know that an active rear diff was an option but i seem to have a lock icon over the rear diff on the 4x4i screen, does this mean i have one?

Cheers guys im sure one of you will know better than me.  There is nothing that can't be fixed with a hammer😜😜
FFRR 4.4 SDV8 Autobiography Santorini Black.
KIA E-Niro 4+
2010 LR D4 Commercial 2.7 TDV6