[Guy]

Yes, this one is easy and makes common sense.

The switch actuates a merge solenoid in the rear of the coach that electrically connects the house battery bank and the chassis battery bank. Handy, if the chassis batteries are down and you need a boost to get the coach started. Also useful if you want to charge the chassis batteries with the onboard charger.

Warning leaving them merged all the time gives you NO protection against draining the start (chassis) batteries when dry camping.

The reason it is a two position switch is that the solenoid requires voltage to operate. If it were only to use one bank of batteries for the trigger, then if that bank were dead, you could not merge. Giving you the option of using either bank to trigger the merge switch allows you to use the bank that is not dead.

Richard thank you !

Yes, now I get it.  electrically it has the same result, just changes the supply source for powering the solenoid. Will the gen set only charge the chassis batteries up when it is in the merge position?