PW is correct - most likely headlight switch.
While cleaning switch, if you do not have a multi-meter to test switch, you can use a paperclip or small piece of wire and run a jumper on the harness w/ the switch out (thus isolating it to cause of issue - wiring diagram in Bentley manual. it's been a while since I did but IIRC it's from the large center pin to the one ~ 2 o'clock - if 2 is at top right of a clock in the land down under also
).
Carbon build up is very common on switch/contacts that get fair use... Long forgotten (and in a good way) are days of cleaning or replacing points, rotors and caps. Pressure switches on well pumps have same exact issue. Heck, since we're all car peeps... remember how bummed out you felt when your slot cars first slowed / sputtered and you lost a race to your best friend next door... that was until you learned to use emory paper / eraser / IPA to clean the contacts? Ah the good ole days (for you old guys... not me of course
.
Cleaning thoroughly as it's not an inexpensive part.
Good luck
