the diagram is from the RAVE discs as can be seen shows bulb indicators the led uses the same inputs but the printed circuit board contains electronic components to accommodate the LED's .if you use make a lead with a
fuse and
12v lamp in circuit and connect to
C0230-1 and
C0230-14 the lamp should not light with the
hand brake off but should with hand brake on or fluid level switch activated ,this will confirm that the problem is the panel .
connect to
C0230-1 and
C0230-7 if the lamp is off then the ABS module is not indicating a fault so again would suspect the panel .
not sure how easy it is to gain excess to the printed circuit board to visually check for signs of component failure ,corrosion ,dry joint .if you do gain access to PCB some good images would help greatly for future reference .
attached someones image of PCB but not of good quality and ignore labelling will give you some idea of what to expect
View attachment 204914