Hi Pierre,
Many owners who had hull numbers close to mine +-50 have the same genset. Possibly yours was changed in any event here are photos. Onan frequently changes part numbers for the same part.

Below is a letter I sent a year or so ago.

I have broken a few of these switches over the years. I have done this by reaching over the generator to retrieve something stored behind the genset.

I received a quote from my Onan dealer and on Amazon for around $90- plus tax which is ridiculous.

I tracked down the OEM manufacturer and the cost is about $23- plus a one time set up fee of about $50- I plan on ordering 2 of these. They stated that they make this for ONAN. If anyone is interested please let me know and I can order them for you $33- each plus USPS of about $8.00.

I will order the switches within a week.

Fair Winds,

Eric

SM 376 Kimberlite