CAT 287B Park Brake/Arm Rest Light/Interlock Issue

Have a problem with my 287B (ZSA01752) that the Park Brake light and Arm Rest light (on the top left cluster) don’t illuminate.

This is what I’ve observed:
When I turn the ignition on (not to start position) all the LEDs from the information cluster flash and stay on for a moment (I guess I would describe this as a ‘start up check’). Then all the LED warning/information cluster LEDs go out (even the Park Brake light despite it should stay on initially).
The machine starts up fine.
However,...

CAT 287B Park Brake/Arm Rest Light/Interlock Issue

CAT 287B Park Brake/Arm Rest Light/Interlock Issue