Rear differential lock not working

[m50]

Hi I’m a newbie. I have a 2020 Defender Max HD8 that the rear differential won’t unlock.  I intend to use it in the yard and on the road some also. I just bought this last week and don’t know much about it.  Does anyone have any ideas?

Thanks RB

 

[Andystoy19]

Attached is the section from the manual, FYI 

 

[m50]

Thanks I got it working I think.  Is there supposed to be a marker on the dash display or just the switch lights up?

RB

 

[Andystoy19]

The switch lights up when engaged.