how does a battery boost switch operate?

All good answers!

A little light reading - Intellitec Battery Control Center

This is just one example of multiple configurations. Specifically this version includes the disconnect switches, AUX Start and changing of both the chassis and house batteries from either the alternator or the converter/charger.

Also on Winnebagos the RUN terminal on the ignition switch activates the boost solenoid so the house batteries are charged while driving. The boost solenoid is a continuous duty solenoid.

If it is working right, it operates a big solenoid switch that ties the two battery banks together (engine battery and house batteries).

It is fairly common for the solenoids to go bad.....as they can carry a LOT of current when used.

The switch on the dash energizes a relay to connect the two battery systems together, chassis and coach. On some the relay is also the charge relay that allows the chassis alternator to charge the coach batteries.