By turn on do you mean start (engine running) or just turning the key to on?
If engine running that is normal. If just turning on it sounds like a bad earth somewhere and sneak current is going to ground via the oil pressure light, switch and the engine block.
Hi, thanks for the reply.. that part is indeed working good. Engine running.. no light, engine off... light. Btw.. i noticed also that since that problem.. the battery light does not turn on when starting or turn the key to “on”
The problem is solved.. the alternator had an internal fault.. mounted a new ( refurbished ) alternator this morning, and everything works fine again... for now[emoji6]