The potentiometer (dimmer) is the probable cause. My 240's dash lights stopped working shortly after I purchased it. Unfortunately, I didn't realize that the tripometer doubled as a dimmer. In eliminating what seemed obvious, I replaced all of the bulbs, and the headlight switch (twice). In trying to find answers to solve this problem, I ran into this website (why didn't I find this site first
). Anyway, I tapped it with a rubber hammer a few times & twisted it bit, & it's worked ever since. The oil & highbeam indicators seem like a separate issue. Hope this helps.