What engine do you have? Gas or DP.
I can only tell you my experience with a gasser.
Mine had 'several' solenoids! And it is a common problem for one to ho out.
Back in the day there was only one solenoid and it was 'not' part of the starter. Now a days the solenoid on the starter is sold as one as an assembly.
That said. I had Mobil RV repair come out.
I turned key while he checked each solenoid. Saying a prayer it was not the one on the starter!
Luckily it was not the one connected to the starter. Inexpensive part and a couple of minutes to replace.