Did you enter the default user code ? Or code you usually use?
These panels do go faulty where they lose there nvm memory etc and usually this occurs how you described, but would also have reset the codes I believe
What's opposite it or near it
It's time for pictures , don't worry if install is dodgy , so are mine
But your saying when no one is near it right , from a distance
You enter eng , remove the keypad , wire up new one and then add new one , system should see no keypad
I assume you have no app system so can't do it from virtual keypad
Or just add new one as keypad 2 and delete keypad 1 , don't really make much difference for you
Or you know who to go see right ?
Some of the keypads had touch sensitivity problems , these are all usually exchanged via the supplier , hkc can't tell you which ones are at fault , and over time the problem gets worse where they keypad starts pressing its own buttons as such
If you bought without warranties unlikely you can exchange and will just have to hope it's just the Illumination bit
Unless you have some knowledge for this it will be difficult.
I would remove the fuse again
You need logically check for electrical power ,
How do you know the mains power is not disconnected somewhere? After inserting fuse that would be your first check , by maybe using a mains tester.