There are at least five different ONAN solenoids. They have different internal wiring connections. If a "standard" ford solenoid is installed, the circuit board could be presented with a 12 volt "ground".
Remove the original solenoid and check the ONAN number stanped on the back of the mounting strap. Most auto parts places have a cross reference list.
JimL
Jim & Jane Latour
08 Chevy 3500HD, crew cab, dually, Duramax/Allison
Crossroads Cruiser CR305SK14, Onan 3.6KY
Retired AF CMS (E9) Power Generation and Onan RV genset Level III tech
Grand Strand Sams
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