My P335 Surprise has no deck light installed. Don’t know why but that’s how it is.

This winter I want to replace the steam light for a Osculati LED combined steam light/deck light.

However I’m not sure there even is a fuse in the push button for the deck light. Of course I can measure when opening (again) the instrument panel. Still I’d like to know how to replace a fuse in case one gets blown. I’m not sure I have spare fuses on board.

Do you mean the thermal circuit breakers in the switch panel? A web search for " ETA 1110-F112-P1M1-10A" , replacing the 10A with the value you want, should find a number of suppliers. They are around £20 each in the UK. I replaced a good few of them as they had gone intermittent and would occasionally shut down the electronics or turn the tricolour into a flashing distress signal. They are supposed to be self-cleaning but probably not designed for long term marine use. They were simple enough to replace using a soldering iron.

Ewan